Package 'phyloseq'

Title: Handling and analysis of high-throughput microbiome census data
Description: phyloseq provides a set of classes and tools to facilitate the import, storage, analysis, and graphical display of microbiome census data.
Authors: Paul J. McMurdie <[email protected]>, Susan Holmes <[email protected]>, with contributions from Gregory Jordan and Scott Chamberlain
Maintainer: Paul J. McMurdie <[email protected]>
License: AGPL-3
Version: 1.51.0
Built: 2024-11-30 03:35:16 UTC
Source: https://github.com/bioc/phyloseq

Help Index


Handling and analysis of high-throughput phylogenetic sequence data.

Description

There are already several ecology and phylogenetic packages available in R, including the adephylo, vegan, ade4, picante, ape, phangorn, phylobase, and OTUbase packages. These can already take advantage of many of the powerful statistical and graphics tools available in R. However, prior to phyloseq a user must devise their own methods for parsing the output of their favorite OTU clustering application, and, as a consequence, there is also no standard within Bioconductor (or R generally) for storing or sharing the suite of related data objects that describe a phylogenetic sequencing project. The phyloseq package seeks to address these issues by providing a related set of S4 classes that internally manage the handling tasks associated with organizing, linking, storing, and analyzing phylogenetic sequencing data. phyloseq additionally provides some convenience wrappers for input from common clustering applications, common analysis pipelines, and native implementation of methods that are not available in other R packages.

Author(s)

Paul J. McMurdie II [email protected]

References

www.stanford.edu/~mcmurdie


Method extensions to extraction operator for phyloseq objects.

Description

See the documentation for the Extract generic, defined in the R base-package for the expected behavior.

Usage

## S4 method for signature 'otu_table,ANY,ANY,ANY'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'sample_data,ANY,ANY,ANY'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'taxonomyTable,ANY,ANY,ANY'
x[i, j, ..., drop = TRUE]

## S4 method for signature 'XStringSet,character,ANY,ANY'
x[i]

Arguments

x

object from which to extract element(s) or in which to replace element(s).

i

indices specifying elements to extract or replace. Indices are numeric or character vectors or empty (missing) or NULL. Numeric values are coerced to integer as by as.integer (and hence truncated towards zero). Character vectors will be matched to the names of the object (or for matrices/arrays, the dimnames): see ‘Character indices’ below for further details.

For [-indexing only: i, j, ... can be logical vectors, indicating elements/slices to select. Such vectors are recycled if necessary to match the corresponding extent. i, j, ... can also be negative integers, indicating elements/slices to leave out of the selection.

When indexing arrays by [ a single argument i can be a matrix with as many columns as there are dimensions of x; the result is then a vector with elements corresponding to the sets of indices in each row of i.

An index value of NULL is treated as if it were integer(0).

j

See Extract

...

See Extract

drop

For matrices and arrays. If TRUE the result is coerced to the lowest possible dimension (see the examples). This only works for extracting elements, not for the replacement. See drop for further details.

Details

One special exception to standard behavior of these methods in phyloseq is that the drop argument is set internally to FALSE. This helps avoid bugs during complicated subsetting with multiple components, where it is necessary to be able to use a two dimensional indexing even if one of those dimensions has only 1 rank. Put another way, these phyloseq-defined extractions never collapse their result into a vector. See the documentation of Extract for more information about the drop argument.

See Also

Extract

Examples

data(esophagus)
nrow(otu_table(esophagus))
nrow(otu_table(esophagus)[1:5, ])

Universal slot accessor function for phyloseq-class.

Description

This function is used internally by many accessors and in many functions/methods that need to access a particular type of component data. If something is wrong, or the slot is missing, the expected behavior is that this function will return NULL. Thus, the output can be tested by is.null as verification of the presence of a particular data component. Unlike the component-specific accessors (e.g. otu_table, or phy_tree), the default behavior is not to stop with an error if the desired slot is empty. In all cases this is controlled by the errorIfNULL argument, which can be set to TRUE if an error is desired.

Usage

access(physeq, slot, errorIfNULL=FALSE)

Arguments

physeq

(Required). phyloseq-class.

slot

(Required). A character string indicating the slot (not data class) of the component data type that is desired.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default FALSE.

Value

Returns the component object specified by the argument slot. Returns NULL if slot does not exist. Returns physeq as-is if it is a component class that already matches the slot name.

See Also

getslots.phyloseq, merge_phyloseq

Examples

#
## data(GlobalPatterns)
## access(GlobalPatterns, "tax_table")
## access(GlobalPatterns, "phy_tree")
## access(otu_table(GlobalPatterns), "otu_table")
## # Should return NULL:
## access(otu_table(GlobalPatterns), "sample_data")
## access(otuTree(GlobalPatterns), "sample_data")
## access(otuSam(GlobalPatterns), "phy_tree")

Build a tax_table from a named possibly-jagged list

Description

Build a tax_table from a named possibly-jagged list

Usage

build_tax_table(taxlist)

Arguments

taxlist

(Required). A list in which each element is a vector of taxonomic assignments named by rank. Every element of every vector must be named by the rank it represents. Every element of the list (every vector) should correspond to a single OTU and be named for that OTU.

Value

A tax_table (taxonomyTable-class) that has been built from taxlist. The OTU names of this output will be the element names of taxlist, and a separate taxonomic rank (column) will be included for each unique rank found among the element names of each vector in the list. NA_character_ is the default value of elements in the tax_table for which there is no corresponding information in taxlist.

See Also

import_biom import_qiime

Examples

taxvec1 = c("Root", "k__Bacteria", "p__Firmicutes", "c__Bacilli", "o__Bacillales", "f__Staphylococcaceae")
 parse_taxonomy_default(taxvec1)
 parse_taxonomy_greengenes(taxvec1)
 taxvec2 = c("Root;k__Bacteria;p__Firmicutes;c__Bacilli;o__Bacillales;f__Staphylococcaceae")
 parse_taxonomy_qiime(taxvec2)
 taxlist1 = list(OTU1=parse_taxonomy_greengenes(taxvec1), OTU2=parse_taxonomy_qiime(taxvec2))
 taxlist2 = list(OTU1=parse_taxonomy_default(taxvec1), OTU2=parse_taxonomy_qiime(taxvec2))
 build_tax_table(taxlist1)
 build_tax_table(taxlist2)

(Data) Enterotypes of the human gut microbiome (2011)

Description

Published in Nature in early 2011, this work compared (among other things), the faecal microbial communities from 22 subjects using complete shotgun DNA sequencing. Authors further compared these microbial communities with the faecal communities of subjects from other studies. A total of 280 faecal samples / subjects are represented in this dataset, and 553 genera. The authors claim that the data naturally clumps into three community-level clusters, or “enterotypes”, that are not immediately explained by sequencing technology or demographic features of the subjects, but with potential relevance to understanding human gut microbiota.

Details

abstract from research article (quoted):

Our knowledge of species and functional composition of the human gut microbiome is rapidly increasing, but it is still based on very few cohorts and little is known about variation across the world. By combining 22 newly sequenced faecal metagenomes of individuals from four countries with previously published data sets, here we identify three robust clusters (referred to as enterotypes hereafter) that are not nation or continent specific. We also confirmed the enterotypes in two published, larger cohorts, indicating that intestinal microbiota variation is generally stratified, not continuous. This indicates further the existence of a limited number of well-balanced host-microbial symbiotic states that might respond differently to diet and drug intake. The enterotypes are mostly driven by species composition, but abundant molecular functions are not necessarily provided by abundant species, highlighting the importance of a functional analysis to understand microbial communities. Although individual host properties such as body mass index, age, or gender cannot explain the observed enterotypes, data-driven marker genes or functional modules can be identified for each of these host properties. For example, twelve genes significantly correlate with age and three functional modules with the body mass index, hinting at a diagnostic potential of microbial markers.

(end quote)

Author(s)

Arumugam, M., Raes, J., et al.

References

Arumugam, M., et al. (2011). Enterotypes of the human gut microbiome.

Nature, 473(7346), 174-180.

http://www.nature.com/doifinder/10.1038/nature09944 See supplemental information for subject data.

OTU-clustered data was downloaded from the publicly-accessible:

http://www.bork.embl.de/Docu/Arumugam_et_al_2011/downloads.html

Examples

data(enterotype)
ig <- make_network(enterotype, "samples", max.dist=0.3)
plot_network(ig, enterotype, color="SeqTech", shape="Enterotype", line_weight=0.3, label=NULL)

(Data) Small example dataset from a human esophageal community (2004)

Description

Includes just 3 samples, 1 each from 3 subjects. Although the research article mentions 4 subjects, only 3 are included in this dataset.

Details

abstract from research article (quoted):

The esophagus, like other luminal organs of the digestive system, provides a potential environment for bacterial colonization, but little is known about the presence of a bacterial biota or its nature. By using broad-range 16S rDNA PCR, biopsies were examined from the normal esophagus of four human adults. The 900 PCR products cloned represented 833 unique sequences belonging to 41 genera, or 95 species-level operational taxonomic units (SLOTU); 59 SLOTU were homologous with culture-defined bacterial species, 34 with 16S rDNA clones, and two were not homologous with any known bacterial 16S rDNA. Members of six phyla, Firmicutes, Bacteroides, Actinobacteria, Proteobacteria, Fusobacteria, and TM7, were represented. A large majority of clones belong to 13 of the 41 genera (783/900, 87%), or 14 SLOTU (574/900, 64%) that were shared by all four persons. Streptococcus (39%), Prevotella (17%), and Veilonella (14%) were most prevalent. The present study identified 56-79% of SLOTU in this bacterial ecosystem. Most SLOTU of esophageal biota are similar or identical to residents of the upstream oral biota, but the major distinction is that a large majority (82%) of the esophageal bacteria are known and cultivable. These findings provide evidence for a complex but conserved bacterial population in the normal distal esophagus.

(end quote)

A description of the 16S rRNA sequence processing can be found on the mothur-wiki at the link below. A cutoff of 0.10 was used for OTU clustering in that example, and it is taken here as well to create example data, esophagus, which was easily imported with the import_mothur() function.

Author(s)

Pei et al. [email protected]

References

Pei, Z., Bini, E. J., Yang, L., Zhou, M., Francois, F., & Blaser, M. J. (2004). Bacterial biota in the human distal esophagus. Proceedings of the National Academy of Sciences of the United States of America, 101(12), 4250-4255. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC384727

mothur-processed files and the sequence data can be downloaded from a zip-file, along with additional description, from the following URL: http://www.mothur.org/wiki/Esophageal_community_analysis

Examples

data(esophagus)
UniFrac(esophagus, weighted=TRUE)
# How to re-create the esophagus dataset using import_mothur function
mothlist  <- system.file("extdata", "esophagus.fn.list.gz", package="phyloseq")
mothgroup <- system.file("extdata", "esophagus.good.groups.gz", package="phyloseq")
mothtree  <- system.file("extdata", "esophagus.tree.gz", package="phyloseq")
show_mothur_cutoffs(mothlist)
cutoff    <- "0.10"
esophman  <- import_mothur(mothlist, mothgroup, mothtree, cutoff)

(Data) Global patterns of 16S rRNA diversity at a depth of millions of sequences per sample (2011)

Description

Published in PNAS in early 2011. This work compared the microbial communities from 25 environmental samples and three known “mock communities” – a total of 9 sample types – at a depth averaging 3.1 million reads per sample. Authors were able to reproduce diversity patterns seen in many other published studies, while also invesitigating technical issues/bias by applying the same techniques to simulated microbial communities of known composition.

Details

abstract from research article (quoted):

The ongoing revolution in high-throughput sequencing continues to democratize the ability of small groups of investigators to map the microbial component of the biosphere. In particular, the coevolution of new sequencing platforms and new software tools allows data acquisition and analysis on an unprecedented scale. Here we report the next stage in this coevolutionary arms race, using the Illumina GAIIx platform to sequence a diverse array of 25 environmental samples and three known “mock communities” at a depth averaging 3.1 million reads per sample. We demonstrate excellent consistency in taxonomic recovery and recapture diversity patterns that were previously reported on the basis of metaanalysis of many studies from the literature (notably, the saline/nonsaline split in environmental samples and the split between host-associated and free-living communities). We also demonstrate that 2,000 Illumina single-end reads are sufficient to recapture the same relationships among samples that we observe with the full dataset. The results thus open up the possibility of conducting large-scale studies analyzing thousands of samples simultaneously to survey microbial communities at an unprecedented spatial and temporal resolution.

(end quote)

Many thanks to J. Gregory Caporaso for directly providing the OTU-clustered data files for inclusion in this package.

Author(s)

Caporaso, J. G., et al.

References

Caporaso, J. G., et al. (2011). Global patterns of 16S rRNA diversity at a depth of millions of sequences per sample. PNAS, 108, 4516-4522. PMCID: PMC3063599

The primary article can be viewed/downloaded at: http://www.pnas.org/content/108/suppl.1/4516.short

See Also

The examples on the phyloseq wiki page for plot_ordination show many more examples:

https://github.com/joey711/phyloseq/wiki/plot_ordination

Examples

data(GlobalPatterns)
plot_richness(GlobalPatterns, x="SampleType", measures=c("Observed", "Chao1", "Shannon"))

(Data) Reproducibility of soil microbiome data (2011)

Description

Published in early 2011, this work compared 24 separate soil microbial communities under four treatment conditions via multiplexed/barcoded 454-pyrosequencing of PCR-amplified 16S rRNA gene fragments. The authors found differences in the composition and structure of microbial communities between soil treatments. As expected, the soil microbial communities were highly diverse, with a staggering 16,825 different OTUs (species) observed in the included dataset. Interestingly, this study used a larger number of replicates than previous studies of this type, for a total of 56 samples, and the putatively low resampling rate of species between replicated sequencing trials (“OTU overlap”) was a major concern by the authors.

Details

This dataset contains an experiment-level (phyloseq-class) object, which in turn contains the taxa-contingency table and soil-treatment table as otu_table-class and sample_data-class components, respectively.

This data was imported from raw files supplied directly by the authors via personal communication for the purposes of including as an example in the phyloseq-package. As this data is sensitive to choices in OTU-clustering parameters, attempts to recreate the otu_table from the raw sequencing data may give slightly different results than the table provided here.

abstract from research article (quoted):

To determine the reproducibility and quantitation of the amplicon sequencing-based detection approach for analyzing microbial community structure, a total of 24 microbial communities from a long-term global change experimental site were examined. Genomic DNA obtained from each community was used to amplify 16S rRNA genes with two or three barcode tags as technical replicates in the presence of a small quantity (0.1% wt/wt) of genomic DNA from Shewanella oneidensis MR-1 as the control. The technical reproducibility of the amplicon sequencing-based detection approach is quite low, with an average operational taxonomic unit (OTU) overlap of 17.2%+/-2.3% between two technical replicates, and 8.2%+/-2.3% among three technical replicates, which is most likely due to problems associated with random sampling processes. Such variations in technical replicates could have substantial effects on estimating beta-diversity but less on alpha-diversity. A high variation was also observed in the control across different samples (for example, 66.7-fold for the forward primer), suggesting that the amplicon sequencing-based detection approach could not be quantitative. In addition, various strategies were examined to improve the comparability of amplicon sequencing data, such as increasing biological replicates, and removing singleton sequences and less-representative OTUs across biological replicates. Finally, as expected, various statistical analyses with preprocessed experimental data revealed clear differences in the composition and structure of microbial communities between warming and non-warming, or between clipping and non-clipping. Taken together, these results suggest that amplicon sequencing-based detection is useful in analyzing microbial community structure even though it is not reproducible and quantitative. However, great caution should be taken in experimental design and data interpretation when the amplicon sequencing-based detection approach is used for quantitative analysis of the beta-diversity of microbial communities.

(end quote)

Author(s)

Jizhong Zhou, et al.

References

Zhou, J., Wu, L., Deng, Y., Zhi, X., Jiang, Y.-H., Tu, Q., Xie, J., et al. Reproducibility and quantitation of amplicon sequencing-based detection. The ISME Journal. (2011) 5(8):1303-1313. doi:10.1038/ismej.2011.11

The article can be accessed online at http://www.nature.com/ismej/journal/v5/n8/full/ismej201111a.html

Examples

# Load the data
data(soilrep)
################################################################################
# Alpha diversity (richness) example. Accept null hypothesis: 
# No convincing difference in species richness between warmed/unwarmed soils.
################################################################################
# Graphically compare richness between the different treatments.
man.col <- c(WC="red", WU="brown", UC="blue", UU="darkgreen")
plot_richness(soilrep, x="Treatment", color="Treatment", measures=c("Observed", "Chao1", "Shannon"))

An S4 placeholder for the dist class.

Description

See dist for details about this type of a distance matrix object.

See Also

dist, setOldClass


Calculate distance, dissimilarity

Description

Takes a phyloseq-class object and method option, and returns a distance object suitable for certain ordination methods and other distance-based analyses. Only sample-wise distances are currently supported (the type argument), but eventually species-wise (OTU-wise) distances may be supported as well.

Usage

distance(physeq, method, type = "samples", ...)

## S4 method for signature 'phyloseq,ANY'
distance(physeq, method)

## S4 method for signature 'otu_table,character'
distance(physeq, method,
  type = "samples", ...)

## S4 method for signature 'phyloseq,character'
distance(physeq, method, type = "samples",
  ...)

Arguments

physeq

(Required). A phyloseq-class or an otu_table-class object. The latter is only appropriate for methods that do not require any additional data (one-table). For example, the “wunifrac” option (UniFrac) requires phyloseq-class that contains both an otu_table and a phylogenetic tree (phylo).

method

(Required). A character string. Provide one of the currently supported options. See distanceMethodList for a detailed list of the supported options here, and links to accompanying documentation.

Note that for the common definition of Jaccard distance using the vegan-package implementation, an additional argument is needed, with the full call having the form: distance(physeq, method = "jaccard", binary = TRUE)

The following methods are implemented explicitly within the phyloseq-package, and accessed by the following method options:

"unifrac"

Original (unweighted) UniFrac distance, UniFrac

"wunifrac"

weighted-UniFrac distance, UniFrac

"dpcoa"

sample-wise distance used in Double Principle Coordinate Analysis, DPCoA

"jsd"

Jensen-Shannon Divergence, JSD

Alternatively, you can provide a character string that defines a custom distance method, if it has the form described in designdist.

type

(Optional). A character string. The type of pairwise comparisons being calculated: sample-wise or taxa-wise. The default is c("samples").

...

Additional arguments passed on to the appropriate distance function, determined by the method argument.

Details

Depending on the method argument, distance() wraps one of UniFrac, DPCoA, JSD, vegdist, betadiver, designdist, or dist.

Value

An object of class “dist” suitable for certain ordination methods and other distance-based analyses.

See Also

plot_ordination, UniFrac, DPCoA, JSD, vegdist, betadiver, designdist, dist.

Examples

data(esophagus)
distance(esophagus, "uunifrac") # Unweighted UniFrac
distance(esophagus, "wunifrac") # weighted UniFrac
distance(esophagus, "jaccard", binary = TRUE) # vegdist jaccard
distance(esophagus, "gower") # vegdist option "gower"
distance(esophagus, "g") # designdist method option "g"
distance(esophagus, "minkowski") # invokes a method from the base dist() function.
distance(esophagus, "(A+B-2*J)/(A+B)") # designdist custom distance
distanceMethodList
help("distance")

List of distance method keys supported in distance

Description

Distance methods should be specified by exact string match. Cannot do partial matching for all options, because too many similar options in downstream method dispatch.

Usage

distanceMethodList

Format

A list of character vectors. Every entry specifies a supported distance method. Names in the list indicate which downstream function is being utilized for further details. Same functions are linked in the itemized list below.

unifrac

UniFrac

wunifrac

UniFrac

dpcoa

DPCoA

jsd

JSD

manhattan

vegdist

euclidean

vegdist

canberra

vegdist

bray

vegdist

kulczynski

vegdist

jaccard

vegdist

gower

vegdist

altGower

vegdist

morisita

vegdist

horn

vegdist

mountford

vegdist

raup

vegdist

binomial

vegdist

chao

vegdist

cao

vegdist

w

betadiver

-

betadiver

c

betadiver

wb

betadiver

r

betadiver

I

betadiver

e

betadiver

t

betadiver

me

betadiver

j

betadiver

sor

betadiver

m

betadiver

-

betadiver

co

betadiver

cc

betadiver

g

betadiver

-

betadiver

l

betadiver

hk

betadiver

rlb

betadiver

sim

betadiver

gl

betadiver

z

betadiver

maximum

dist

binary

dist

minkowski

dist

ANY

designdist

See Also

distance

Examples

distanceMethodList

Calculate Double Principle Coordinate Analysis (DPCoA) using phylogenetic distance

Description

Function uses abundance (otu_table-class) and phylogenetic (phylo) components of a phyloseq-class experiment-level object to perform a Double Principle Coordinate Analysis (DPCoA), relying heavily on the underlying (and more general) function, dpcoa. The distance object ultimately provided is the square root of the cophenetic/patristic (cophenetic.phylo) distance between the species, which is always Euclidean.

Although this distance is Euclidean, for numerical reasons it will sometimes look non-Euclidean, and a correction will be performed. See correction argument.

Usage

DPCoA(physeq, correction = cailliez, scannf = FALSE, ...)

Arguments

physeq

(Required). A phyloseq-class object containing, at a minimum, abundance (otu_table-class) and phylogenetic (phylo) components. As a test, the accessors otu_table and phy_tree should return an object without error.

correction

(Optional). A function. The function must be able to take a non-Euclidean distance object, and return a new distance object that is Euclidean. If testing a distance object, try is.euclid.

Although the distance matrix should always be Euclidean, for numerical reasons it will sometimes appear non-Euclidean and a correction method must be applied. Two recommended correction methods are cailliez and lingoes. The default is cailliez, but not for any particularly special reason. If the distance matrix is Euclidian, no correction will be performed, regardless of the value of the correction argument.

scannf

(Optional). Logical. Default is FALSE. This is passed directly to dpcoa, and causes a barplot of eigenvalues to be created if TRUE. This is not included in ... because the default for dpcoa is TRUE, although in many expected situations we would want to suppress creating the barplot.

...

Additional arguments passed to dpcoa.

Value

A dpcoa-class object (see dpcoa).

Author(s)

Julia Fukuyama [email protected]. Adapted for phyloseq by Paul J. McMurdie.

References

Pavoine, S., Dufour, A.B. and Chessel, D. (2004) From dissimilarities among species to dissimilarities among communities: a double principal coordinate analysis. Journal of Theoretical Biology, 228, 523-537.

See Also

dpcoa

Examples

# # # # # # Esophagus
data(esophagus)
eso.dpcoa <- DPCoA(esophagus)
eso.dpcoa
plot_ordination(esophagus, eso.dpcoa, "samples")
plot_ordination(esophagus, eso.dpcoa, "species")
plot_ordination(esophagus, eso.dpcoa, "biplot")
#
#
# # # # # # GlobalPatterns
data(GlobalPatterns)
# subset GP to top-150 taxa (to save computation time in example)
keepTaxa <- names(sort(taxa_sums(GlobalPatterns), TRUE)[1:150])
GP       <- prune_taxa(keepTaxa, GlobalPatterns)
# Perform DPCoA
GP.dpcoa <- DPCoA(GP)
plot_ordination(GP, GP.dpcoa, color="SampleType")

Summarize alpha diversity

Description

Performs a number of standard alpha diversity estimates, and returns the results as a data.frame. Strictly speaking, this function is not only estimating richness, despite its name. It can operate on the cumulative population of all samples in the dataset, or by repeating the richness estimates for each sample individually. NOTE: You must use untrimmed datasets for meaningful results, as these estimates (and even the “observed” richness) are highly dependent on the number of singletons. You can always trim the data later on if needed, just not before using this function.

Usage

estimate_richness(physeq, split = TRUE, measures = NULL)

Arguments

physeq

(Required). phyloseq-class, or alternatively, an otu_table-class. The data about which you want to estimate the richness.

split

(Optional). Logical. Should a separate set of richness estimates be performed for each sample? Or alternatively, pool all samples and estimate richness of the entire set.

measures

(Optional). Default is NULL, meaning that all available alpha-diversity measures will be included. Alternatively, you can specify one or more measures as a character vector of measure names. Values must be among those supported: c("Observed", "Chao1", "ACE", "Shannon", "Simpson", "InvSimpson", "Fisher").

Value

A data.frame of the richness estimates, and their standard error.

See Also

Check out the custom plotting function, plot_richness, for easily showing the results of different estimates, with method-specific error-bars. Also check out the internal functions borrowed from the vegan package:

estimateR

diversity

fisherfit

Examples

## There are many more interesting examples at the phyloseq online tutorials.
## http://joey711.github.com/phyloseq/plot_richness-examples
 data("esophagus")
 # Default is all available measures
 estimate_richness(esophagus)
 # Specify just one:
 estimate_richness(esophagus, measures="Observed")
 # Specify a few:
 estimate_richness(esophagus, measures=c("Observed", "InvSimpson", "Shannon", "Chao1"))

Export environment (ENV) file for UniFrac Server.

Description

Creates the environment table that is needed for the original UniFrac algorithm. Useful for cross-checking, or if want to use UniFrac server. Optionally the ENV-formatted table can be returned to the R workspace, and the tree component can be exported as Nexus format (Recommended).

Usage

export_env_file(physeq, file = "", writeTree = TRUE, return = FALSE)

Arguments

physeq

(Required). Experiment-level (phyloseq-class) object. Ideally this also contains the phylogenetic tree, which is also exported by default.

file

(Optional). The file path for export. If not-provided, the expectation is that you will want to set return to TRUE, and manipulate the ENV table on your own. Default is "", skipping the ENV file from being written to a file.

writeTree

(Optional). Write the phylogenetic tree as well as the the ENV table. Default is TRUE.

return

(Optional). Should the ENV table be returned to the R workspace? Default is FALSE.

Examples

# # Load example data
# data(esophagus)
# export_env_file(esophagus, "~/Desktop/esophagus.txt")

Export a distance object as .names and .dist files for mothur

Description

The purpose of this function is to allow a user to easily export a distance object as a pair of files that can be immediately imported by mothur for OTU clustering and related analysis. A distance object can be created in R in a number of ways, including via cataloguing the cophentic distances of a tree object.

Usage

export_mothur_dist(x, out=NULL, makeTrivialNamesFile=NULL)

Arguments

x

(Required). A "dist" object, or a symmetric matrix.

out

(Optional). The desired output filename for the .dist file, OR left NULL, the default, in which case the mothur-formated distance table is returned to R standard out.

makeTrivialNamesFile

(Optional). Default NULL. The desired name of the .names file. If left NULL, the file name will be a modified version of the out argument.

Value

A character vector of the different cutoff values contained in the file. For a given set of arguments to the cluster() command from within mothur, a number of OTU-clustering results are returned in the same list file. The exact cutoff values used by mothur can vary depending on the input data. This simple function returns the cutoffs that were actually included in the mothur output. This an important extra step prior to importing the OTUs with the import_mothur_otulist() function.

Examples

#
data(esophagus) 
myDistObject <- as.dist(ape::cophenetic.phylo(phy_tree(esophagus)))
export_mothur_dist(myDistObject)

Filter taxa based on across-sample OTU abundance criteria

Description

This function is directly analogous to the genefilter function for microarray filtering, but is used for filtering OTUs from phyloseq objects. It applies an arbitrary set of functions — as a function list, for instance, created by filterfun — as across-sample criteria, one OTU at a time. It takes as input a phyloseq object, and returns a logical vector indicating whether or not each OTU passed the criteria. Alternatively, if the "prune" option is set to FALSE, it returns the already-trimmed version of the phyloseq object.

Usage

filter_taxa(physeq, flist, prune=FALSE)

Arguments

physeq

(Required). A phyloseq-class object that you want to trim/filter.

flist

(Required). A function or list of functions that take a vector of abundance values and return a logical. Some canned useful function types are included in the genefilter-package.

prune

(Optional). A logical. Default FALSE. If TRUE, then the function returns the pruned phyloseq-class object, rather than the logical vector of taxa that passed the filter.

Value

A logical vector equal to the number of taxa in physeq. This can be provided directly to prune_taxa as first argument. Alternatively, if prune==TRUE, the pruned phyloseq-class object is returned instead.

See Also

filterfun, genefilter_sample, filterfun_sample

Examples

data("enterotype")
 require("genefilter")
 flist    <- filterfun(kOverA(5, 2e-05))
 ent.logi <- filter_taxa(enterotype, flist)
 ent.trim <- filter_taxa(enterotype, flist, TRUE)
 identical(ent.trim, prune_taxa(ent.logi, enterotype)) 
 identical(sum(ent.logi), ntaxa(ent.trim))
 filter_taxa(enterotype, flist, TRUE)

A sample-wise filter function builder analogous to filterfun.

Description

See the filterfun, from the Bioconductor repository, for a taxa-/gene-wise filter (and further examples).

Usage

filterfun_sample(...)

Arguments

...

A comma-separated list of functions.

Value

An enclosure (function) that itself will return a logical vector, according to the functions provided in the argument list, evaluated in order. The output of filterfun_sample is appropriate for the ‘flist’ argument to the genefilter_sample method.

See Also

filterfun, genefilter_sample

Examples

# Use simulated abundance matrix
set.seed(711)
testOTU <- otu_table(matrix(sample(1:50, 25, replace=TRUE), 5, 5), taxa_are_rows=FALSE)
f1  <- filterfun_sample(topk(2))
wh1 <- genefilter_sample(testOTU, f1, A=2)
wh2 <- c(TRUE, TRUE, TRUE, FALSE, FALSE)
prune_taxa(wh1, testOTU)
prune_taxa(wh2, testOTU)

Estimate the gap statistic on an ordination result

Description

This is a wrapper for the clusGap function, expecting an ordination result as the main data argument.

Usage

gapstat_ord(ord, axes = c(1:2), type = "sites",
  FUNcluster = function(x, k) {     list(cluster = pam(x, k, cluster.only
  = TRUE)) }, K.max = 8, ...)

Arguments

ord

(Required). An ordination object. The precise class can vary. Any ordination classes supported internally by the phyloseq package should work, ultimately by passing to the scores function or its internal extensions in phyloseq.

axes

(Optional). The ordination axes that you want to include.

type

(Optional). One of "sites" (the vegan package label for samples) or "species" (the vegan package label for OTUs/taxa). Default is "sites".

FUNcluster

(Optional). This is passed to clusGap. The documentation is copied here for convenience: a function which accepts as first argument a (data) matrix like x, second argument, say (the number of desired clusters) k, where k >= 2, and returns a list with a component named (or shortened to) cluster which is a vector of length n = nrow(x) of integers in 1:k determining the clustering or grouping of the n observations. The default value is the following function, which wraps partitioning around medoids, pam:

function(x, k){list(cluster = pam(x, k, cluster.only=TRUE))}

Any function that has these input/output properties (performing a clustering) will suffice. The more appropriate the clustering method, the better chance your gap statistic results will be useful.

K.max

(Optional). A single positive integer value. It indicates the maximum number of clusters that will be considered. Value must be at least two. This is passed to clusGap.

...

(Optional). Additional named parameters passed on to clusGap. For example, the method argument provides for extensive options regarding the method by which the “optimal” number of clusters is computed from the gap statistics (and their standard deviations). See the clusGap documentation for more details.

Value

An object of S3 class "clusGap", basically a list with components. See the clusGap documentation for more details.

Examples

data("soilrep")
sord  = ordinate(soilrep, "PCoA", "bray")
# Evaluate axes with scree plot
plot_scree(sord)
# Gap Statistic
gs = gapstat_ord(sord, axes=1:3, verbose=FALSE)
# plot_ordination(soilrep, sord,  color="Treatment")
plot_clusgap(gs)
print(gs, method="Tibs2001SEmax")

Filter OTUs with arbitrary function, sample-wise.

Description

A general OTU trimming function for selecting OTUs that satisfy some criteria within the distribution of each sample, and then also an additional criteria for number of samples that must pass. This is a genefilter-like function that only considers sample-wise criteria. The number of acceptable samples is used as the final criteria (set by the argument A) to determine whether or not the taxa should be retained (TRUE) or not (FALSE). Just like with genefilter, a logical having length equal to nrow()/ntaxa is returned, indicating which should be kept. This output can be provided directly to OTU trimming function, prune_taxa. By contrast, genefilter, of the genefilter package in Bioconductor, works only on the rows of a matrix. Note that, because otu_table-class inherits directly from the matrix-class, an unmodified otu_table can be provided to genefilter, but be mindful of the orientation of the otu_table (use taxa_are_rows), and transpose (t) if needed.

Usage

genefilter_sample(X, flist, A=1)

## S4 method for signature 'matrix'
genefilter_sample(X, flist, A = 1)

## S4 method for signature 'otu_table'
genefilter_sample(X, flist, A = 1)

## S4 method for signature 'phyloseq'
genefilter_sample(X, flist, A = 1)

Arguments

X

The object that needs trimming. Can be matrix, otu_table, or higher- order phyloseq classes that contain an otu_table.

flist

An enclosure object, typically created with filterfun_sample

A

An integer. The number of samples in which a taxa / OTUs passed the filter for it to be labeled TRUE in the output logical vector.

Value

A logical vector with names equal to taxa_names (or rownames, if matrix).

See Also

genefilter, filterfun_sample, t, prune_taxa

Examples

#
## testOTU <- otu_table(matrix(sample(1:50, 25, replace=TRUE), 5, 5), taxa_are_rows=FALSE)
## f1  <- filterfun_sample(topk(2))
## wh1 <- genefilter_sample(testOTU, f1, A=2)
## wh2 <- c(TRUE, TRUE, TRUE, FALSE, FALSE)
## prune_taxa(wh1, testOTU)
## prune_taxa(wh2, testOTU)
## 
## tax_table1 <- tax_table(matrix("abc", 5, 5))
## prune_taxa(wh1, tax_table1)
## prune_taxa(wh2, tax_table1)

Returns all abundance values for species i.

Description

This is a simple accessor function for investigating a single species-of-interest.

Usage

get_sample(physeq, i)

## S4 method for signature 'otu_table'
get_sample(physeq, i)

## S4 method for signature 'phyloseq'
get_sample(physeq, i)

Arguments

physeq

(Required). otu_table-class, or phyloseq-class.

i

(Required). A single taxa/species/OTU ID for which you want to know the abundance in each sample.

Value

An integer vector of the abundance values for each sample in physeq for species i

See Also

get_taxa taxa_names sample_names

Examples

data(esophagus)
taxa_names(esophagus)
get_sample(esophagus, "59_5_19")

Returns all abundance values of sample i.

Description

This is a simple accessor function for investigating a single sample-of-interest.

Usage

get_taxa(physeq, i)

## S4 method for signature 'otu_table'
get_taxa(physeq, i)

## S4 method for signature 'phyloseq'
get_taxa(physeq, i)

Arguments

physeq

(Required). otu_table-class, or phyloseq-class.

i

(Required). A single sample for which you want to know the abundance of each species. Can be integer for index value, or sample name.

Value

An integer vector of the abundance values for each species in physeq for sample i

See Also

get_sample taxa_names sample_names

Examples

data(esophagus)
sample_names(esophagus)
get_taxa(esophagus, "B")

Get a unique vector of the observed taxa at a particular taxonomic rank

Description

This is a simple accessor function to make it more convenient to determine the different taxa present for a particular taxonomic rank in a given phyloseq-class object.

Usage

get_taxa_unique(physeq, taxonomic.rank=rank_names(physeq)[1], errorIfNULL=TRUE)

Arguments

physeq

(Required). taxonomyTable-class, or phyloseq-class.

taxonomic.rank

(Optional). Character. The taxonomic rank to use. Must select from the set indicated by get_taxa_unique. Default is to take the first column of the taxonomyTable component.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE.

Value

Character vector. Unique vector of the observed taxa at a particular taxonomic rank

See Also

get_taxa taxa_names sample_names

Examples

data(enterotype)
get_taxa_unique(enterotype)
data(GlobalPatterns)
get_taxa_unique(GlobalPatterns, "Family")

Get the values for a particular variable in sample_data

Description

This is a simple accessor function for streamlining access to values/vectors/factors/etc contained in the sample_data.

Usage

get_variable(physeq, varName)

Arguments

physeq

(Required). sample_data-class, or phyloseq-class.

varName

(Required). Character string of the variable name in sample_data. Use sample_variables(physeq) for available variables in your object.

Value

Data. The clas of the data depends on what the contents of sample_data.

See Also

get_taxa taxa_names sample_names

sample_variables

Examples

# Load the GlobalPatterns dataset into the workspace environment
data(GlobalPatterns)
# Look at the different values for SampleType 
get_variable(GlobalPatterns, "SampleType")

Return the non-empty slot names of a phyloseq object.

Description

Like getSlots, but returns the class name if argument is component data object.

Usage

getslots.phyloseq(physeq)

Arguments

physeq

A phyloseq-class object. If physeq is a component data class, then just returns the class of physeq.

Value

identical to getSlots. A named character vector of the slot classes of a particular S4 class, where each element is named by the slot name it represents. If physeq is a component data object, then a vector of length (1) is returned, named according to its slot name in the phyloseq-class.

See Also

merge_phyloseq

Examples

#
 data(GlobalPatterns)
 getslots.phyloseq(GlobalPatterns)
 data(esophagus)
 getslots.phyloseq(esophagus)

Universal import method (wrapper) for phyloseq-package

Description

A user must still understand the additional arguments required for each type of import data. Those arguments are described in detail at the tool-specific import_* links below. Each clustering tool / package / pipeline has its own idiosyncratic set of file names / types, and it remains the responsibility of the user to understand which file-path should be provided to each argument for the particular importing submethod. This method merely provides a central documentation and method-name, and the arguments are passed along as-is.

Usage

import(pipelineName, ...)

Arguments

pipelineName

(Required). Character string. The name of the analysis tool / pipeline / package that created the OTU-cluster data or other data that you now want to import. Current options are c("mothur", "pyrotagger", "QIIME", "RDP"), and only the first letter is necessary.

...

(Required). Additional named arguments providing file paths, and possible other paramaters to the desired tool-specific import function.

Value

In most cases a phyloseq-class will be returned, though the included component data will vary by pipeline/tool, and also by the types of data files provided. The expected behavior is to return the most-comprehensive object possible, given the provided arguments and pipeline/tool.

References

BIOM: http://www.biom-format.org/

mothur: http://www.mothur.org/wiki/Main_Page

PyroTagger: http://pyrotagger.jgi-psf.org/

QIIME: http://qiime.org/

RDP pipeline: http://pyro.cme.msu.edu/index.jsp

See Also

For BIOM format, see: import_biom

For mothur, see: import_mothur

Separate tools for mothur are also: show_mothur_cutoffs import_mothur_dist export_mothur_dist

For PyroTagger, see: import_pyrotagger_tab

For QIIME legacy format, see: import_qiime

For RDP pipeline, see: import_RDP_cluster

import_RDP_otu

Examples

## See documentation of a specific import function

Import phyloseq data from biom-format file

Description

New versions of QIIME produce a more-comprehensive and formally-defined JSON file format, called biom file format:

Usage

import_biom(BIOMfilename, 
 treefilename=NULL, refseqfilename=NULL, refseqFunction=readDNAStringSet, refseqArgs=NULL,
 parseFunction=parse_taxonomy_default, parallel=FALSE, version=1.0, ...)

Arguments

BIOMfilename

(Required). A character string indicating the file location of the BIOM formatted file. This is a JSON formatted file, specific to biological datasets, as described in http://www.qiime.org/svn_documentation/documentation/biom_format.htmlthe biom-format home page. In principle, this file should include you OTU abundance data (OTU table), your taxonomic classification data (taxonomy table), as well as your sample data, for instance what might be in your “sample map” in QIIME. A phylogenetic tree is not yet supported by biom-format, and so is a separate argument here. If, for some reason, your biom-format file is missing one of these mentioned data types but you have it in a separate file, you can first import the data that is in the biom file using this function, import_biom, and then “merge” the remaining data after you have imported with other tools using the relatively general-purpose data merging function called merge_phyloseq.

treefilename

(Optional). Default value is NULL. A file representing a phylogenetic tree or a phylo object. Files can be NEXUS or Newick format. See read_tree for more details. Also, if using a recent release of the GreenGenes database tree, try the read_tree_greengenes function – this should solve some issues specific to importing that tree. If provided, the tree should have the same OTUs/tip-labels as the OTUs in the other files. Any taxa or samples missing in one of the files is removed from all. As an example from the QIIME pipeline, this tree would be a tree of the representative 16S rRNA sequences from each OTU cluster, with the number of leaves/tips equal to the number of taxa/species/OTUs, or the complete reference database tree that contains the OTU identifiers of every OTU in your abundance table. Note that this argument can be a tree object (phylo-class) for cases where the tree has been — or needs to be — imported separately, as in the case of the GreenGenes tree mentioned earlier (coderead_tree_greengenes).

refseqfilename

(Optional). Default NULL. The file path of the biological sequence file that contains at a minimum a sequence for each OTU in the dataset. Alternatively, you may provide an already-imported XStringSet object that satisfies this condition. In either case, the names of each OTU need to match exactly the taxa_names of the other components of your data. If this is not the case, for example if the data file is a FASTA format but contains additional information after the OTU name in each sequence header, then some additional parsing is necessary, which you can either perform separately before calling this function, or describe explicitly in a custom function provided in the (next) argument, refseqFunction. Note that the XStringSet class can represent any arbitrary sequence, including user-defined subclasses, but is most-often used to represent RNA, DNA, or amino acid sequences. The only constraint is that this special list of sequences has exactly one named element for each OTU in the dataset.

refseqFunction

(Optional). Default is readDNAStringSet, which expects to read a fasta-formatted DNA sequence file. If your reference sequences for each OTU are amino acid, RNA, or something else, then you will need to specify a different function here. This is the function used to read the file connection provided as the the previous argument, refseqfilename. This argument is ignored if refseqfilename is already a XStringSet class.

refseqArgs

(Optional). Default NULL. Additional arguments to refseqFunction. See XStringSet-io for details about additional arguments to the standard read functions in the Biostrings package.

parseFunction

(Optional). A function. It must be a function that takes as its first argument a character vector of taxonomic rank labels for a single OTU and parses and names each element (an optionally removes unwanted elements). Further details and examples of acceptable functions are provided in the documentation for parse_taxonomy_default. There are many variations on taxonomic nomenclature, and naming conventions used to store that information in various taxonomic databases and phylogenetic assignment algorithms. A popular database, http://greengenes.lbl.gov/cgi-bin/nph-index.cgigreengenes, has its own custom parsing function provided in the phyloseq package, parse_taxonomy_greengenes, and more can be contributed or posted as code snippets as needed. They can be custom-defined by a user immediately prior to the the call to import_biom, and this is a suggested first step to take when trouble-shooting taxonomy-related errors during file import.

parallel

(Optional). Logical. Wrapper option for .parallel parameter in plyr-package functions. If TRUE, apply parsing functions in parallel, using parallel backend provided by foreach and its supporting backend packages. One caveat, plyr-parallelization currently works most-cleanly with multicore-like backends (Mac OS X, Unix?), and may throw warnings for SNOW-like backends. See the example below for code invoking multicore-style backend within the doParallel package.

Finally, for many datasets a parallel import should not be necessary because a serial import will be just as fast and the import is often only performed one time; after which the data should be saved as an RData file using the save function.

version

(Optional). Numeric. The expected version number of the file. As the BIOM format evolves, version-specific importers may be available by adjusting the version value. Default is 1.0. Not yet implemented. Parsing of the biom-format is done mostly by the biom package now available in CRAN.

...

Additional parameters passed on to read_tree.

Details

“The biom file format (canonically pronounced ‘biome’) is designed to be a general-use format for representing counts of observations in one or more biological samples. BIOM is a recognized standard for the Earth Microbiome Project and is a Genomics Standards Consortium candidate project.”

http://biom-format.org/

Value

A phyloseq-class object.

References

biom-format

See Also

import

import_qiime

read_tree

read_tree_greengenes

read_biom

biom_data

sample_metadata

observation_metadata

XStringSet-io

Examples

# An included example of a rich dense biom file
rich_dense_biom  <- system.file("extdata", "rich_dense_otu_table.biom",  package="phyloseq")
import_biom(rich_dense_biom,  parseFunction=parse_taxonomy_greengenes)
# An included example of a sparse dense biom file
rich_sparse_biom <- system.file("extdata", "rich_sparse_otu_table.biom", package="phyloseq")
import_biom(rich_sparse_biom, parseFunction=parse_taxonomy_greengenes)
# # # Example code for importing large file with parallel backend
# library("doParallel")
# registerDoParallel(cores=6)
# import_biom("my/file/path/file.biom", parseFunction=parse_taxonomy_greengenes, parallel=TRUE)

Read a UniFrac-formatted ENV file.

Description

Convenience wrapper function to read the environment-file, as formatted for input to the UniFrac server (http://bmf2.colorado.edu/unifrac/). The official format of these files is that each row specifies (in order) the sequence name, source sample, and (optionally) the number of times the sequence was observed.

Usage

import_env_file(envfilename, tree=NULL, sep="\t", ...)

Arguments

envfilename

(Required). A charater string of the ENV filename (relative or absolute)

tree

(Optional). phylo-class object to be paired with the output otu_table.

sep

A character string indicating the delimiter used in the file. The default is "\t".

...

Additional parameters passed on to read.table.

Value

An otu_table-class, or phyloseq-class if a phylo-class argument is provided to tree.

References

http://bmf2.colorado.edu/unifrac/

See Also

import

tip_glom

Examples

# import_env_file(myEnvFile, myTree)

General function for importing mothur data files into phyloseq.

Description

Technically all parameters are optional, but if you don't provide any file connections, then nothing will be returned. While the list and group files are the first two arguments for legacy-compatibility reasons, we don't recommend that you use these file types with modern (large) datasets. They are comically inefficient, as they store the name of every sequencing read in both files. The mothur package provides conversions utilities to create other more-efficient formats, which we recommend, like the shared file for an OTU table. Alternatively, mothur also provides a utility to create a biom-format file that is independent of OTU clustering platform. Biom-format files should be imported not with this function, but with import_biom. The resulting objects after import should be identical in R.

Usage

import_mothur(mothur_list_file = NULL, mothur_group_file = NULL,
  mothur_tree_file = NULL, cutoff = NULL, mothur_shared_file = NULL,
  mothur_constaxonomy_file = NULL,
  parseFunction = parse_taxonomy_default)

Arguments

mothur_list_file

(Optional). The list file name / location produced by mothur.

mothur_group_file

(Optional). The name/location of the group file produced by mothur's make.group() function. It contains information about the sample source of individual sequences, necessary for creating a species/taxa abundance table (otu_table). See http://www.mothur.org/wiki/Make.group

mothur_tree_file

(Optional). A tree file, presumably produced by mothur, and readable by read_tree. The file probably has extension ".tree".

cutoff

(Optional). A character string indicating the cutoff value, (or "unique"), that matches one of the cutoff-values used to produce the OTU clustering results contained within the list-file created by mothur (and specified by the mothur_list_file argument). The default is to take the largest value among the cutoff values contained in the list file. If only one cutoff is included in the file, it is taken and this argument does not need to be specified. Note that the cluster() function within the mothur package will often produce a list file with multiple cutoff values, even if a specific cutoff is specified. It is suggested that you check which cutoff values are available in a given list file using the show_mothur_cutoffs function.

mothur_shared_file

(Optional). A shared file produced by mothur.

mothur_constaxonomy_file

(Optional). A consensus taxonomy file produced by mothur.

parseFunction

(Optional). A specific function used for parsing the taxonomy string. See parse_taxonomy_default for an example. If the default is used, this function expects a semi-colon delimited taxonomy string, with no additional rank specifier. A common taxonomic database is GreenGenes, and in recent versions its taxonomy entries include a prefix, which is best cleaved and used to precisely label the ranks (parse_taxonomy_greengenes).

Value

The object class depends on the provided arguments. A phyloseq object is returned if enough data types are provided. If only one data component can be created from the data, it is returned.

FASTER (recommended for larger data sizes):

If only a mothur_constaxonomy_file is provided, then a taxonomyTable-class object is returned.

If only a mothur_shared_file is provided, then an otu_table object is returned.

SLOWER (but fine for small file sizes):

The list and group file formats are extremely inefficient for large datasets, and they are not recommended. The mothur software provides tools for converting to other file formats, such as a so-called “shared” file. You should provide a shared file, or group/list files, but not both at the same time. If only a list and group file are provided, then an otu_table object is returned. Similarly, if only a list and tree file are provided, then only a tree is returned (phylo-class).

References

http://www.mothur.org/wiki/Main_Page

Schloss, P.D., et al., Introducing mothur: Open-source, platform-independent, community-supported software for describing and comparing microbial communities. Appl Environ Microbiol, 2009. 75(23):7537-41.

Examples

# # The following example assumes you have downloaded the esophagus example
# # dataset from the mothur wiki:
# # "http://www.mothur.org/wiki/Esophageal_community_analysis"
# # "http://www.mothur.org/w/images/5/55/Esophagus.zip"
# # The path on your machine may (probably will) vary
# mothur_list_file  <- "~/Downloads/mothur/Esophagus/esophagus.an.list"
# mothur_group_file <- "~/Downloads/mothur/Esophagus/esophagus.good.groups"
# mothur_tree_file  <- "~/Downloads/mothur/Esophagus/esophagus.tree"
# # # Actual examples follow:
# show_mothur_cutoffs(mothur_list_file)
# test1 <- import_mothur(mothur_list_file, mothur_group_file, mothur_tree_file)
# test2 <- import_mothur(mothur_list_file, mothur_group_file, mothur_tree_file, cutoff="0.02")
# # Returns just a tree
# import_mothur(mothur_list_file, mothur_tree_file=mothur_tree_file)
# # Returns just an otu_table
# import_mothur(mothur_list_file, mothur_group_file=mothur_group_file)
# # Returns an error
# import_mothur(mothur_list_file)
# # Should return an "OMG, you must provide the list file" error
# import_mothur()

Import mothur-formatted distance file

Description

The mothur application will produce a file containing the pairwise distances between all sequences in a dataset. This distance matrix can be the basis for OTU cluster designations. R also has many built-in or off-the-shelf tools for dealing with distance matrices.

Usage

import_mothur_dist(mothur_dist_file)

Arguments

mothur_dist_file

Required. The distance file name / location produced by mothur.

Value

A distance matrix object describing all sequences in a dataset.

See Also

import_mothur

Examples

# # Take a look at the dataset shown here as an example:
# # "http://www.mothur.org/wiki/Esophageal_community_analysis"
# # find the file ending with extension ".dist", download to your system
# # The location of your file may vary
# mothur_dist_file <- "~/Downloads/mothur/Esophagus/esophagus.dist"
# myNewDistObject  <- import_mothur_dist(mothur_dist_file)

Imports a tab-delimited version of the pyrotagger output file.

Description

PyroTagger is a web-server that takes raw, barcoded 16S rRNA amplicon sequences and returns an excel spreadsheet (".xls") with both abundance and taxonomy data. It also includes some confidence information related to the taxonomic assignment.

Usage

import_pyrotagger_tab(pyrotagger_tab_file, 
strict_taxonomy=FALSE, keep_potential_chimeras=FALSE)

Arguments

pyrotagger_tab_file

(Required). A character string. The name of the tab-delimited pyrotagger output table.

strict_taxonomy

(Optional). Logical. Default FALSE. Should the taxonomyTable component be limited to just taxonomic data? Default includes all fields from the pyrotagger file.

keep_potential_chimeras

(Optional). Logical. Default FALSE. The pyrotagger output also includes OTUs that are tagged by pyrotagger as likely chimeras. These putative chimeric OTUs can be retained if set to TRUE. The putative chimeras are excluded by default.

Details

PyroTagger is created and maintained by the Joint Genome Institute at "http://pyrotagger.jgi-psf.org/"

The typical output form PyroTagger is a spreadsheet format ".xls", which poses additional import challenges. However, virtually all spreadsheet applications support the ".xls" format, and can further export this file in a tab-delimited format. It is recommended that you convert the xls-file without any modification (as tempting as it might be once you have loaded it) into a tab-delimited text file. Deselect any options to encapsulate fields in quotes, as extra quotes around each cell's contents might cause problems during file processing. These quotes will also inflate the file-size, so leave them out as much as possible, while also resisting any temptation to modify the xls-file “by hand”.

A highly-functional and free spreadsheet application can be obtained as part of the cross-platform OpenOffice suite. It works for the above required conversion. Go to "http://www.openoffice.org/".

It is regrettable that this importer does not take the xls-file directly as input. However, because of the moving-target nature of spreadsheet file formats, there is limited support for direct import of these formats into R. Rather than add to the dependency requirements of emphphyloseq and the relative support of these xls-support packages, it seems more efficient to choose an arbitrary delimited text format, and focus on the data structure in the PyroTagger output. This will be easier to support in the long-run.

Value

An otuTax object containing both the otu_table and TaxonomyTable data components, parsed from the pyrotagger output.

References

http://pyrotagger.jgi-psf.org/

Examples

## New_otuTaxObject <- import_pyrotagger_tab(pyrotagger_tab_file)

Import function to read the now legacy-format QIIME OTU table.

Description

QIIME produces several files that can be directly imported by the phyloseq-package. Originally, QIIME produced its own custom format table that contained both OTU-abundance and taxonomic identity information. This function is still included in phyloseq mainly to accommodate these now-outdated files. Recent versions of QIIME store output in the biom-format, an emerging file format standard for microbiome data. If your data is in the biom-format, if it ends with a .biom file name extension, then you should use the import_biom function instead.

Usage

import_qiime(otufilename = NULL, mapfilename = NULL,
  treefilename = NULL, refseqfilename = NULL,
  refseqFunction = readDNAStringSet, refseqArgs = NULL,
  parseFunction = parse_taxonomy_qiime, verbose = TRUE, ...)

Arguments

otufilename

(Optional). A character string indicating the file location of the OTU file. The combined OTU abundance and taxonomic identification file, tab-delimited, as produced by QIIME under default output settings. Default value is NULL.

mapfilename

(Optional). The QIIME map file is required for processing barcoded primers in QIIME as well as some of the post-clustering analysis. This is a required input file for running QIIME. Its strict formatting specification should be followed for correct parsing by this function. Default value is NULL.

treefilename

(Optional). Default value is NULL. A file representing a phylogenetic tree or a phylo object. Files can be NEXUS or Newick format. See read_tree for more details. Also, if using a recent release of the GreenGenes database tree, try the read_tree_greengenes function – this should solve some issues specific to importing that tree. If provided, the tree should have the same OTUs/tip-labels as the OTUs in the other files. Any taxa or samples missing in one of the files is removed from all. As an example from the QIIME pipeline, this tree would be a tree of the representative 16S rRNA sequences from each OTU cluster, with the number of leaves/tips equal to the number of taxa/species/OTUs, or the complete reference database tree that contains the OTU identifiers of every OTU in your abundance table. Note that this argument can be a tree object (phylo-class) for cases where the tree has been — or needs to be — imported separately, as in the case of the GreenGenes tree mentioned earlier (coderead_tree_greengenes).

refseqfilename

(Optional). Default NULL. The file path of the biological sequence file that contains at a minimum a sequence for each OTU in the dataset. Alternatively, you may provide an already-imported XStringSet object that satisfies this condition. In either case, the names of each OTU need to match exactly the taxa_names of the other components of your data. If this is not the case, for example if the data file is a FASTA format but contains additional information after the OTU name in each sequence header, then some additional parsing is necessary, which you can either perform separately before calling this function, or describe explicitly in a custom function provided in the (next) argument, refseqFunction. Note that the XStringSet class can represent any arbitrary sequence, including user-defined subclasses, but is most-often used to represent RNA, DNA, or amino acid sequences. The only constraint is that this special list of sequences has exactly one named element for each OTU in the dataset.

refseqFunction

(Optional). Default is readDNAStringSet, which expects to read a fasta-formatted DNA sequence file. If your reference sequences for each OTU are amino acid, RNA, or something else, then you will need to specify a different function here. This is the function used to read the file connection provided as the the previous argument, refseqfilename. This argument is ignored if refseqfilename is already a XStringSet class.

refseqArgs

(Optional). Default NULL. Additional arguments to refseqFunction. See XStringSet-io for details about additional arguments to the standard read functions in the Biostrings package.

parseFunction

(Optional). An optional custom function for parsing the character string that contains the taxonomic assignment of each OTU. The default parsing function is parse_taxonomy_qiime, specialized for splitting the ";"-delimited strings and also attempting to interpret greengenes prefixes, if any, as that is a common format of the taxonomy string produced by QIIME.

verbose

(Optional). A logical. Default is TRUE. Should progresss messages be catted to standard out?

...

Additional arguments passed to read_tree

Details

Other related files include the mapping-file that typically stores sample covariates, converted naturally to the sample_data-class component data type in the phyloseq-package. QIIME may also produce a phylogenetic tree with a tip for each OTU, which can also be imported specified here or imported separately using read_tree.

See "http://www.qiime.org/" for details on using QIIME. While there are many complex dependencies, QIIME can be downloaded as a pre-installed linux virtual machine that runs “off the shelf”.

The different files useful for import to phyloseq are not collocated in a typical run of the QIIME pipeline. See the main phyloseq vignette for an example of where ot find the relevant files in the output directory.

Value

A phyloseq-class object.

References

http://qiime.org/

“QIIME allows analysis of high-throughput community sequencing data.” J Gregory Caporaso, Justin Kuczynski, Jesse Stombaugh, Kyle Bittinger, Frederic D Bushman, Elizabeth K Costello, Noah Fierer, Antonio Gonzalez Pena, Julia K Goodrich, Jeffrey I Gordon, Gavin A Huttley, Scott T Kelley, Dan Knights, Jeremy E Koenig, Ruth E Ley, Catherine A Lozupone, Daniel McDonald, Brian D Muegge, Meg Pirrung, Jens Reeder, Joel R Sevinsky, Peter J Turnbaugh, William A Walters, Jeremy Widmann, Tanya Yatsunenko, Jesse Zaneveld and Rob Knight; Nature Methods, 2010; doi:10.1038/nmeth.f.303

See Also

phyloseq

merge_phyloseq

read_tree

read_tree_greengenes

XStringSet-io

Examples

otufile <- system.file("extdata", "GP_otu_table_rand_short.txt.gz", package="phyloseq")
 mapfile <- system.file("extdata", "master_map.txt", package="phyloseq")
 trefile <- system.file("extdata", "GP_tree_rand_short.newick.gz", package="phyloseq")
 import_qiime(otufile, mapfile, trefile)

Import now legacy-format QIIME OTU table as a list of two matrices.

Description

Now a legacy-format, older versions of QIIME produced an OTU file that typically contains both OTU-abundance and taxonomic identity information in a tab-delimted table. If your file ends with the extension .biom, or if you happen to know that it is a biom-format file, or if you used default settings in a version of QIIME of 1.7 or greater, then YOU SHOULD USE THE BIOM-IMPORT FUNCTION instead, import_biom.

Usage

import_qiime_otu_tax(file, parseFunction = parse_taxonomy_qiime,
  verbose = TRUE, parallel = FALSE)

Arguments

file

(Required). The path to the qiime-formatted file you want to import into R. Can be compressed (e.g. .gz, etc.), though the details may be OS-specific. That is, Windows-beware.

parseFunction

(Optional). An optional custom function for parsing the character string that contains the taxonomic assignment of each OTU. The default parsing function is parse_taxonomy_qiime, specialized for splitting the ";"-delimited strings and also attempting to interpret greengenes prefixes, if any, as that is a common format of the taxonomy string produced by QIIME.

verbose

(Optional). A logical. Default is TRUE. Should progresss messages be catted to standard out?

parallel

(Optional). Logical. Should the parsing be performed in parallel?. Default is FALSE. Only a few steps are actually parallelized, and for most datasets it will actually be faster and more efficient to keep this set to FALSE. Also, to get any benefit at all, you will need to register a parallel “backend” through one of the backend packages supported by the foreach-package.

Details

This function uses chunking to perform both the reading and parsing in blocks of optional size, thus constrain the peak memory usage. feature should make this importer accessible to machines with modest memory, but with the caveat that the full numeric matrix must be a manageable size at the end, too. In principle, the final tables will be large, but much more efficiently represented than the character-stored numbers. If total memory for storing the numeric matrix becomes problematic, a switch to a sparse matrix representation of the abundance – which is typically well-suited to this data – might provide a solution.

Value

A list of two matrices. $otutab contains the OTU Table as a numeric matrix, while $taxtab contains a character matrix of the taxonomy assignments.

See Also

import

merge_phyloseq

phyloseq

import_qiime

read_tree

read_tree_greengenes

import_env_file

Examples

otufile <- system.file("extdata", "GP_otu_table_rand_short.txt.gz", package="phyloseq")
 import_qiime_otu_tax(otufile)

Import just sample_data file from QIIME pipeline.

Description

QIIME produces several files that can be analyzed in the phyloseq-package, This includes the map-file, which is an important input to QIIME that can also indicate sample covariates. It is converted naturally to the sample_data component data type in phyloseq-package, based on the R data.frame.

Usage

import_qiime_sample_data(mapfilename)

Arguments

mapfilename

(Required). A character string or connection. That is, any suitable file argument to the read.table function. The name of the QIIME map file required for processing pyrosequencing tags in QIIME as well as some of the post-clustering analysis. This is a required input file for running QIIME. Its strict formatting specification is expected by this function, do not attempt to modify it manually once it has worked properly in QIIME.

Details

See import_qiime for more information about QIIME. It is also the suggested function for importing QIIME-produced data files.

Value

A sample_data object.

See Also

import

merge_phyloseq

phyloseq

import_qiime

import_qiime_otu_tax

import_env_file

Examples

mapfile <- system.file("extdata", "master_map.txt", package = "phyloseq")
 import_qiime_sample_data(mapfile)

Import RDP cluster file and return otu_table (abundance table).

Description

The RDP cluster pipeline (specifically, the output of the complete linkage clustering step) has no formal documentation for the ".clust" file or its apparent sequence naming convention.

Usage

import_RDP_cluster(RDP_cluster_file)

Arguments

RDP_cluster_file

A character string. The name of the ".clust" file produced by the the complete linkage clustering step of the RDP pipeline.

Details

http://pyro.cme.msu.edu/index.jsp

The cluster file itself contains the names of all sequences contained in input alignment. If the upstream barcode and aligment processing steps are also done with the RDP pipeline, then the sequence names follow a predictable naming convention wherein each sequence is named by its sample and sequence ID, separated by a "_" as delimiter:

"sampleName_sequenceIDnumber"

This import function assumes that the sequence names in the cluster file follow this convention, and that the sample name does not contain any "_". It is unlikely to work if this is not the case. It is likely to work if you used the upstream steps in the RDP pipeline to process your raw (barcoded, untrimmed) fasta/fastq data.

This function first loops through the ".clust" file and collects all of the sample names that appear. It secondly loops through each OTU ("cluster"; each row of the cluster file) and sums the number of sequences (reads) from each sample. The resulting abundance table of OTU-by-sample is trivially coerced to an otu_table object, and returned.

Value

An otu_table object parsed from the ".clust" file.

References

http://pyro.cme.msu.edu/index.jsp


Import new RDP OTU-table format

Description

Recently updated tools on RDP Pyro site make it easier to import Pyrosequencing output into R. The modified tool “Cluster To R Formatter” can take a cluster file (generated from RDP Clustering tools) to create a community data matrix file for distance cutoff range you are interested in. The resulting output file is a tab-delimited file containing the number of sequences for each sample for each OTU. The OTU header naming convention is "OTU_" followed by the OTU number in the cluster file. It pads “0”s to make the OTU header easy to sort. The OTU numbers are not necessarily in order.

Usage

import_RDP_otu(otufile)

Arguments

otufile

(Optional). A character string indicating the file location of the OTU file, produced/exported according to the instructions above.

Value

A otu_table-class object.

See Also

An alternative “cluster” file importer for RDP results: import_RDP_cluster

The main RDP-pyrosequencing website http://pyro.cme.msu.edu/index.jsp

Examples

otufile <- system.file("extdata", "rformat_dist_0.03.txt.gz", package="phyloseq")
### the gzipped file is automatically recognized, and read using R-connections
ex_otu  <- import_RDP_otu(otufile)
class(ex_otu)
ntaxa(ex_otu)
nsamples(ex_otu)
sample_sums(ex_otu)
head(t(ex_otu))

Import UPARSE file format

Description

UPARSE is an algorithm for OTU-clustering implemented within usearch. At last check, the UPARSE algortihm was accessed via the -cluster_otu option flag. For details about installing and running usearch, please refer to the usearch website. For details about the output format, please refer to the uparse format definition.

Usage

import_uparse(upFile, omitChimeras = TRUE, countTable = TRUE,
  OTUtable = TRUE, verbose = TRUE)

Arguments

upFile

(Required). A file location character string or connection corresponding to the file that contains the UPARSE output table. This is passed directly to fread. Please see its file argument documentation for further links and details.

omitChimeras

(Optional). logical(1). Default is TRUE. Whether to omit entries that correspond to sequences/OTUs that were identified as chimeras.

countTable

(Optional). logical(1). Default is TRUE. Whether to return the result as a wide-format table with dimensions OTU-by-sample, or to leave the table in its original sparse long-format that might be more suitable for certain data.table operations. If TRUE, entries corresponding to the same sample and OTU have their counts summed.

OTUtable

(Optional). logical(1). Default is TRUE. Whether to coerce the result to otu_table format, or leave it as a data.table format. The former is appropriate for most phyloseq operations, the latter is useful for a lot of custom operations and custom ggplot2 graphics calls.

verbose

(Optional). A logical. Default is TRUE. Should progresss messages be catted to standard out?

Details

Because UPARSE is an external (non-R) application, there is no direct way to continuously check that these suggested arguments and file formats will remain in their current state. If there is a problem, please verify your version of usearch, create a small reproducible example of the problem, and post it as an issue on the phyloseq issues tracker.

See Also

import_usearch_uc

Examples

###

Import usearch table format (.uc) to OTU table

Description

UPARSE is an algorithm for OTU-clustering implemented within usearch. At last check, the UPARSE algortihm was accessed via the -cluster_otu option flag. For details about installing and running usearch, please refer to the usearch website. For details about the output format, please refer to the uc format definition. This importer is intended to read a particular table format output that is generated by usearch, its so-called “cluster format”, a file format that is often given the .uc extension in usearch documentation.

Usage

import_usearch_uc(ucfile, colRead = 9, colOTU = 10,
  readDelimiter = "_", verbose = TRUE)

Arguments

ucfile

(Required). A file location character string or connection corresponding to the file that contains the usearch output table. This is passed directly to read.table. Please see its file argument documentation for further links and details.

colRead

(Optional). Numeric. The column index in the uc-table file that holds the read IDs. The default column index is 9.

colOTU

(Optional). Numeric. The column index in the uc-table file that holds OTU IDs. The default column index is 10.

readDelimiter

(Optional). An R regex as a character string. This should be the delimiter that separates the sample ID from the original ID in the demultiplexed read ID of your sequence file. The default is plain underscore, which in this regex context is "_".

verbose

(Optional). A logical. Default is TRUE. Should progresss messages be catted to standard out?

Details

Because usearch is an external (non-R) application, there is no direct way to continuously check that these suggested arguments and file formats will remain in their current state. If there is a problem, please verify your version of usearch, create a small reproducible example of the problem, and post it as an issue on the phyloseq issues tracker. The version of usearch upon which this import function was created is 7.0.109. Hopefully later versions of usearch maintain this function and format, but the phyloseq team has no way to guarantee this, and so any feedback about this will help maintain future functionality. For instance, it is currently assumed that the 9th and 10th columns of the .uc table hold the read-label and OTU ID, respectively; and it is also assumed that the delimiter between sample-name and read in the read-name entries is a single "_". If this is not true, you may have to update these parameters, or even modify the current implementation of this function.

Also note that there is now a UPARSE-specific output file format, uparseout, and it might make more sense to create and import that file for use in phyloseq. If so, you'll want to import using the import_uparse() function.

See Also

import

import_biom

import_qiime

Examples

usearchfile <- system.file("extdata", "usearch.uc", package="phyloseq")
import_usearch_uc(usearchfile)

Make microbiome network (igraph)

Description

A specialized function for creating a network representation of microbiomes, sample-wise or taxa-wise, based on a user-defined ecological distance and (potentially arbitrary) threshold. The graph is ultimately represented using the igraph-package.

Usage

make_network(physeq, type="samples", distance="jaccard", max.dist = 0.4, 
    keep.isolates=FALSE, ...)

Arguments

physeq

(Required). Default NULL. A phyloseq-class object, or otu_table-class object, on which g is based. phyloseq-class recommended.

type

(Optional). Default "samples". Whether the network should be samples or taxa/OTUs. Supported arguments are "samples", "taxa", where "taxa" indicates using the OTUs/taxaindices, whether they actually represent species or some other taxonomic rank.

NOTE: not all distance methods are supported if "taxa" selected for type. For example, the UniFrac distance and DPCoA cannot be calculated for taxa-wise distances, because they use a taxa-wise tree as part of their calculation between samples, and there is no transpose-equivalent for this tree.

distance

(Optional). Default "jaccard". Any supported argument to the method parameter of the distance function is supported here. Some distance methods, like "unifrac", may take a non-trivial amount of time to calculate, in which case you probably want to calculate the distance matrix separately, save, and then provide it as the argument to distance instead. See below for alternatives).

Alternatively, if you have already calculated the sample-wise distance object, the resulting dist-class object can be provided as distance instead (see examples).

A third alternative is to provide a function that takes a sample-by-taxa matrix (typical vegan orientation) and returns a sample-wise distance matrix.

max.dist

(Optional). Default 0.4. The maximum ecological distance (as defined by distance) allowed between two samples to still consider them “connected” by an edge in the graphical model.

keep.isolates

(Optional). Default FALSE. Logical. Whether to keep isolates (un-connected samples, not microbial isolates) in the graphical model that is returned. Default results in isolates being removed from the object.

...

(Optional). Additional parameters passed on to distance.

Value

A igraph-class object.

See Also

plot_network

Examples

# # Example plots with Enterotype Dataset
data(enterotype)
ig <- make_network(enterotype, max.dist=0.3)
plot_network(ig, enterotype, color="SeqTech", shape="Enterotype", line_weight=0.3, label=NULL)
# 
ig1 <- make_network(enterotype, max.dist=0.2)
plot_network(ig1, enterotype, color="SeqTech", shape="Enterotype", line_weight=0.3, label=NULL)
# 
# # Three methods of choosing/providing distance/distance-method
# Provide method name available to distance() function
ig <- make_network(enterotype, max.dist=0.3, distance="jaccard")
# Provide distance object, already computed
jaccdist <- distance(enterotype, "jaccard")
ih <- make_network(enterotype, max.dist=0.3, distance=jaccdist)
# Provide "custom" function.
ii <- make_network(enterotype, max.dist=0.3, distance=function(x){vegan::vegdist(x, "jaccard")})
# The have equal results:		
all.equal(ig, ih)
all.equal(ig, ii)
# 
# Try out making a trivial "network" of the 3-sample esophagus data,
# with weighted-UniFrac as distance
data(esophagus)
ij <- make_network(esophagus, "samples", "unifrac", weighted=TRUE)

Merge arguments into one phyloseq object.

Description

Takes a comma-separated list of phyloseq objects as arguments, and returns the most-comprehensive single phyloseq object possible.

Usage

merge_phyloseq(...)

Arguments

...

a comma-separated list of phyloseq objects.

Details

Higher-order objects can be created if arguments are appropriate component data types of different classes, and this should mirror the behavior of the phyloseq method, which is the suggested method if the goal is simply to create a higher-order phyloseq object from different data types (1 of each class) describing the same experiment.

By contrast, this method is intended for situations in which one wants to combine multiple higher-order objects, or multiple core component data objects (e.g. more than one otu_table) that should be combined into one object.

Merges are performed by first separating higher-order objects into a list of their component objects; then, merging any component objects of the same class into one object according to the behavior desribed in merge_phyloseq_pair; and finally, building back up a merged-object according to the constructor behavior of the phyloseq method. If the arguments contain only a single component type – several otu_table objects, for example – then a single merged object of that component type is returned.

Value

Merges are performed by first separating higher-order objects into a list of their component objects; then, merging any component objects of the same class into one object according to the behavior desribed in merge_phyloseq_pair; and finally, re-building a merged-object according to the constructor behavior of the phyloseq method. If the arguments contain only a single component type – several otu_table objects, for example – then a single merged object of the relevant component type is returned.

Merges between 2 or more tree objects are ultimately done using consensus from the ape package. This has the potential to limit somewhat the final data object, because trees don't merge with other trees in the same granular manner as data tables, and ultimately the species/taxa in higher-order phyloseq objects will be clipped to what is contained in the tree. If this an issue, the tree component should be ommitted from the argument list.

Examples

#
## # Make a random complex object
## OTU1 <- otu_table(matrix(sample(0:5,250,TRUE),25,10), taxa_are_rows=TRUE)
## tax1 <- tax_table(matrix("abc", 30, 8))
## map1 <- data.frame( matrix(sample(0:3,250,TRUE),25,10), 
##   matrix(sample(c("a","b","c"),150,TRUE), 25, 6) ) 
## map1 <- sample_data(map1)
## exam1 <- phyloseq(OTU1, map1, tax1)
## x <- exam1
## x <- phyloseq(exam1)
## y <- tax_table(exam1)
## merge_phyloseq(x, y)
## merge_phyloseq(y, y, y, y)

Merge pair of phyloseq component data objects of the same class.

Description

Internal S4 methods to combine pairs of objects of classes specified in the phyloseq package. These objects must be component data of the same type (class). This is mainly an internal method, provided to illustrate how merging is performed by the more general merge_phyloseq function.

Usage

merge_phyloseq_pair(x, y)

## S4 method for signature 'otu_table,otu_table'
merge_phyloseq_pair(x, y)

## S4 method for signature 'taxonomyTable,taxonomyTable'
merge_phyloseq_pair(x, y)

## S4 method for signature 'sample_data,sample_data'
merge_phyloseq_pair(x, y)

## S4 method for signature 'phylo,phylo'
merge_phyloseq_pair(x, y)

## S4 method for signature 'XStringSet,XStringSet'
merge_phyloseq_pair(x, y)

Arguments

x

A character vector of the species in object x that you want to keep – OR alternatively – a logical vector where the kept species are TRUE, and length is equal to the number of species in object x. If species is a named logical, the species retained is based on those names. Make sure they are compatible with the taxa_names of the object you are modifying (x).

y

Any phyloseq object.

Details

The merge_phyloseq function is recommended in general.

Special note: non-identical trees are merged using consensus.

Value

A single component data object that matches x and y arguments. The returned object will contain the union of the species and/or samples of each. If there is redundant information between a pair of arguments of the same class, the values in x are used by default. Abundance values are summed for otu_table objects for those elements that describe the same species and sample in x and y.

See Also

merge_phyloseq merge_taxa

Examples

#
## # merge two simulated otu_table objects.
## x  <- otu_table(matrix(sample(0:5,200,TRUE),20,10), taxa_are_rows=TRUE)
## y  <- otu_table(matrix(sample(0:5,300,TRUE),30,10), taxa_are_rows=FALSE)
## xy <- merge_phyloseq_pair(x, y)
## yx <- merge_phyloseq_pair(y, x)
## # merge two simulated tax_table objects
## x <- tax_table(matrix("abc", 20, 6))
## y <- tax_table(matrix("def", 30, 8))
## xy <- merge_phyloseq_pair(x, y)
## # merge two simulated sample_data objects
## x <- data.frame( matrix(sample(0:3,250,TRUE),25,10), 
##   matrix(sample(c("a","b","c"),150,TRUE),25,6) )
## x <- sample_data(x)
## y <- data.frame( matrix(sample(4:6,200,TRUE),20,10), 
##   matrix(sample(c("d","e","f"),120,TRUE),20,8) )
## y <- sample_data(y)
## merge_phyloseq_pair(x, y)
## data.frame(merge_phyloseq_pair(x, y))
## data.frame(merge_phyloseq_pair(y, x))

Merge samples based on a sample variable or factor.

Description

The purpose of this method is to merge/agglomerate the sample indices of a phyloseq object according to a categorical variable contained in a sample_data or a provided factor.

Usage

merge_samples(x, group, fun=mean)

## S4 method for signature 'sample_data'
merge_samples(x, group, fun = mean)

## S4 method for signature 'otu_table'
merge_samples(x, group)

## S4 method for signature 'phyloseq'
merge_samples(x, group, fun = mean)

Arguments

x

(Required). An instance of a phyloseq class that has sample indices. This includes sample_data-class, otu_table-class, and phyloseq-class.

group

(Required). Either the a single character string matching a variable name in the corresponding sample_data of x, or a factor with the same length as the number of samples in x.

fun

(Optional). The function that will be used to merge the values that correspond to the same group for each variable. It must take a numeric vector as first argument and return a single value. Default is mean. Note that this is (currently) ignored for the otu_table, where the equivalent function is sum, but evaluated via rowsum for efficiency.

Details

NOTE: (phylo) trees and taxonomyTable-class are not modified by this function, but returned in the output object as-is.

Value

A phyloseq object that has had its sample indices merged according to the factor indicated by the group argument. The output class matches x.

See Also

merge_taxa, codemerge_phyloseq

Examples

#
data(GlobalPatterns)
GP = GlobalPatterns
mergedGP = merge_samples(GlobalPatterns, "SampleType")
SD = merge_samples(sample_data(GlobalPatterns), "SampleType")
print(SD)
print(mergedGP)
sample_names(GlobalPatterns)
sample_names(mergedGP)
identical(SD, sample_data(mergedGP))
# The OTU abundances of merged samples are summed
# Let's investigate this ourselves looking at just the top10 most abundance OTUs...
OTUnames10 = names(sort(taxa_sums(GP), TRUE)[1:10])
GP10  = prune_taxa(OTUnames10,  GP)
mGP10 = prune_taxa(OTUnames10, mergedGP)
ocean_samples = sample_names(subset(sample_data(GP), SampleType=="Ocean"))
print(ocean_samples)
otu_table(GP10)[, ocean_samples]
rowSums(otu_table(GP10)[, ocean_samples])
otu_table(mGP10)["Ocean", ]

Merge a subset of the species in x into one species/taxa/OTU.

Description

Takes as input an object that describes species/taxa (e.g. phyloseq-class, otu_table-class, phylo-class, taxonomyTable-class), as well as a vector of species that should be merged. It is intended to be able to operate at a low-level such that related methods, such as tip_glom and tax_glom can both reliably call merge_taxa for their respective purposes.

Usage

merge_taxa(x, eqtaxa, archetype=1)

## S4 method for signature 'phyloseq'
merge_taxa(x, eqtaxa,
  archetype = eqtaxa[which.max(taxa_sums(x)[eqtaxa])])

## S4 method for signature 'sample_data'
merge_taxa(x, eqtaxa, archetype = 1L)

## S4 method for signature 'otu_table'
merge_taxa(x, eqtaxa,
  archetype = eqtaxa[which.max(taxa_sums(x)[eqtaxa])])

## S4 method for signature 'phylo'
merge_taxa(x, eqtaxa, archetype = 1L)

## S4 method for signature 'XStringSet'
merge_taxa(x, eqtaxa, archetype = 1L)

## S4 method for signature 'taxonomyTable'
merge_taxa(x, eqtaxa, archetype = 1L)

Arguments

x

(Required). An object that describes species (taxa). This includes phyloseq-class, otu_table-class, taxonomyTable-class, phylo.

eqtaxa

(Required). The species names, or indices, that should be merged together. If length(eqtaxa) < 2, then the object x will be returned safely unchanged.

archetype

(Optional). A single-length numeric or character. The index of eqtaxa, or OTU ID, indicating the species that should be kept to represent the summed/merged group of species/taxa/OTUs. The default is to use the OTU with the largest count total if counts are available, or to use 1 (the first OTU in eqtaxa) otherwise. If archetype is not a valid index or index-name in eqtaxa, the first will be used, and the value in archetype will be used as the index-name for the new species.

Value

The object, x, in its original class, but with the specified species merged into one entry in all relevant components.

See Also

tip_glom, tax_glom, merge_phyloseq, merge_samples

Examples

#
data(esophagus)
tree <- phy_tree(esophagus)
otu  <- otu_table(esophagus)
otutree0 <- phyloseq(otu, tree)
# plot_tree(otutree0)
otutree1 <- merge_taxa(otutree0, 1:8, 2)
# plot_tree(esophagus, ladderize="left")

Import microbio.me/qiime (QIIME-DB) data package

Description

Originally, this function was for accessing microbiome datasets from the microbio.me/qiime public repository from within R. As you can see by clicking on the above link, the QIIME-DB sever is down indefinitely. However, this function will remain supported here in case the FTP server goes back up, and also for phyloseq users that have downloaded one or more data packages prior to the server going down.

Usage

microbio_me_qiime(zipftp, ext = ".zip",
  parsef = parse_taxonomy_greengenes, ...)

Arguments

zipftp

(Required). A character string that is the full URL path to a zipped file that follows the file naming conventions used by microbio.me/qiime. Alternatively, you can simply provide the study number as a single integer or other single-length vector that can be coerced to an integer; this function will complete the remainder of the ftp URL hosted at microbio.me/qiime. For example, instead of the full URL string, "ftp://thebeast.colorado.edu/pub/QIIME_DB_Public_Studies/study_494_split_library_seqs_and_mapping.zip", you could simply provide 494 or "494" as the first ('zipftp') argument.

ext

(Optional). A character string of the expected file extension, which also indicates the compression type, if zipftp is a study number instead of the full path. Note that this argument has no effect if zipftp is the full path, in which case the file extension is read directly from the downloaded file.

parsef

(Optional). The type of taxonomic parsing to use for the OTU taxonomic classification, in the .biom file, if present. This is passed on to import_biom, but unlike that function the default parsing function is parse_taxonomy_greengenes, rather than parse_taxonomy_default, because we know ahead of time that most (or all?) of the taxonomic classifications in the microbio.me/qiime repository will be based on GreenGenes.

...

(Optional, for advanced users). Additional arguments passed to download.file. This is mainly for non-standard links to resources (in this case, a zipped file) that are not being hosted by microbio.me/qiime. If you are using a FTP address or study number from their servers, then you shouldn't need to provide any additional arguments.

Value

A phyloseq-class object if possible, a component if only a component could be imported, or NULL if nothing could be imported after unzipping the file. Keep in mind there is a specific naming-convention that is expected based on the current state of the microbio.me/qiime servers. Several helpful messages are catted to standard out to help let you know the ongoing status of the current download and import process.

See Also

See download.file and url for details about URL formats – including local file addresses – that might work here.

import_biom

import_qiime

Examples

# This should return TRUE on your system if you have internet turned on
# and a standard R installation. Indicates whether this is likely to
# work on your system for a URL or local file, respectively.
capabilities("http/ftp"); capabilities("fifo")
# A working example with a local example file included in phyloseq
zipfile = "study_816_split_library_seqs_and_mapping.zip"
zipfile = system.file("extdata", zipfile, package="phyloseq")
tarfile = "study_816_split_library_seqs_and_mapping.tar.gz"
tarfile = system.file("extdata", tarfile, package="phyloseq")
tarps = microbio_me_qiime(tarfile)
zipps = microbio_me_qiime(zipfile) 
identical(tarps, zipps)
tarps; zipps
plot_heatmap(tarps)
# An example that used to work, before the QIIME-DB server was turned off by its host.
# # Smokers dataset
# smokezip = "ftp://thebeast.colorado.edu/pub/QIIME_DB_Public_Studies/study_524_split_library_seqs_and_mapping.zip"
# smokers1 = microbio_me_qiime(smokezip)
# # Alternatively, just use the study number
# smokers2 = microbio_me_qiime(524)
# identical(smokers1, smokers2)

Multiple testing of taxa abundance according to sample categories/classes

Description

Please note that it is up to you to perform any necessary normalizing / standardizing transformations prior to these tests. See for instance transform_sample_counts.

Usage

mt(physeq, classlabel, minPmaxT = "minP", method = "fdr", ...)

## S4 method for signature 'phyloseq,ANY'
mt(physeq, classlabel, minPmaxT = "minP",
  method = "fdr", ...)

## S4 method for signature 'otu_table,integer'
mt(physeq, classlabel, minPmaxT = "minP",
  method = "fdr", ...)

## S4 method for signature 'otu_table,numeric'
mt(physeq, classlabel, minPmaxT = "minP",
  method = "fdr", ...)

## S4 method for signature 'otu_table,logical'
mt(physeq, classlabel, minPmaxT = "minP",
  method = "fdr", ...)

## S4 method for signature 'otu_table,character'
mt(physeq, classlabel, minPmaxT = "minP",
  method = "fdr", ...)

## S4 method for signature 'otu_table,factor'
mt(physeq, classlabel, minPmaxT = "minP",
  method = "fdr", ...)

Arguments

physeq

(Required). otu_table-class or phyloseq-class. In this multiple testing framework, different taxa correspond to variables (hypotheses), and samples to observations.

classlabel

(Required). A single character index of the sample-variable in the sample_data of physeq that will be used for multiple testing. Alternatively, classlabel can be a custom integer (or numeric coercable to an integer), character, or factor with length equal to nsamples(physeq).

NOTE: the default test applied to each taxa is a two-sample two-sided t.test, WHICH WILL FAIL with an error if you provide a data variable (or custom vector) that contains MORE THAN TWO classes. One alternative to consider is an F-test, by specifying test="f" as an additional argument. See the first example below, and/or further documentation of mt.maxT or mt.minP for other options and formal details.

minPmaxT

(Optional). Character string. "mt.minP" or "mt.maxT". Default is to use "mt.minP".

method

(Optional). Additional multiple-hypthesis correction methods. A character vector from the set p.adjust.methods. Default is "fdr", for the Benjamini and Hochberg (1995) method to control False Discovery Rate (FDR). This argument is passed on to p.adjust, please see that documentation for more details.

...

(Optional). Additional arguments, forwarded to mt.maxT or mt.minP

Value

A dataframe with components specified in the documentation for mt.maxT or mt.minP, respectively.

See Also

mt.maxT

mt.minP

p.adjust

Examples

## # Simple example, testing genera that sig correlate with Enterotypes
data(enterotype)
# Filter samples that don't have Enterotype
x <- subset_samples(enterotype, !is.na(Enterotype))
# (the taxa are at the genera level in this dataset)
res = mt(x, "Enterotype", method="fdr", test="f", B=300)
head(res, 10)
## # Not surprisingly, Prevotella and Bacteroides top the list.
## # Different test, multiple-adjusted t-test, whether samples are ent-2 or not.
## mt(x, get_variable(x, "Enterotype")==2)

Function to avoid plotting node labels

Description

Unlike, nodeplotdefault and nodeplotboot, this function does not return a function, but instead is provided directly to the nodelabf argument of plot_tree to ensure that node labels are not added to the graphic. Please note that you do not need to create or obtain the arguments to this function. Instead, you can provide this function directly to plot_tree and it will know what to do with it. Namely, use it to avoid plotting any node labels.

Usage

nodeplotblank(p, nodelabdf)

Arguments

p

(Required). The plot_tree graphic.

nodelabdf

(Required). The data.frame produced internally in link{plot_tree} to use as data for creating ggplot2-based tree graphics.

Value

The same input object, p, provided as input. Unmodified.

See Also

nodeplotdefault

nodeplotboot

plot_tree

Examples

data("esophagus")
plot_tree(esophagus)
plot_tree(esophagus, nodelabf=nodeplotblank)

Generates a function for labeling bootstrap values on a phylogenetic tree.

Description

Is not a labeling function itself, but returns one. The returned function is specialized for labeling bootstrap values. Note that the function that is returned has two completely different arguments from the four listed here: the plot object already built by earlier steps in plot_tree, and the data.frame that contains the relevant plotting data for the nodes (especially x, y, label), respectively. See nodeplotdefault for a simpler example. The main purpose of this and nodeplotdefault is to provide a useful default function generator for arbitrary and bootstrap node labels, respectively, and also to act as examples of functions that can successfully interact with plot_tree to add node labels to the graphic.

Usage

nodeplotboot(highthresh=95L, lowcthresh=50L, size=2L, hjust=-0.2)

Arguments

highthresh

(Optional). A single integer between 0 and 100. Any bootstrap values above this threshold will be annotated as a black filled circle on the node, rather than the bootstrap percentage value itself.

lowcthresh

(Optional). A single integer between 0 and 100, less than highthresh. Any bootstrap values below this value will not be added to the graphic. Set to 0 or below to add all available values.

size

(Optional). Numeric. Should be positive. The size parameter used to control the text size of taxa labels. Default is 2. These are ggplot2 sizes.

hjust

(Optional). The horizontal justification of the node labels. Default is -0.2.

Value

A function that can add a bootstrap-values layer to the tree graphic. The values are represented in two ways; either as black filled circles indicating very high-confidence nodes, or the bootstrap value itself printed in small text next to the node on the tree.

See Also

nodeplotdefault

nodeplotblank

plot_tree

Examples

nodeplotboot()
nodeplotboot(3, -0.4)

Generates a default node-label function

Description

Is not a labeling function itself, but returns one. The returned function is capable of adding whatever label is on a node. Note that the function that is returned has two completely different arguments to those listed here: the plot object already built by earlier steps in plot_tree, and the data.frame that contains the relevant plotting data for the nodes (especially x, y, label), respectively. See nodeplotboot for a more sophisticated example. The main purpose of this and nodeplotboot is to provide a useful default function generator for arbitrary and bootstrap node labels, respectively, and also to act as examples of functions that will successfully interact with plot_tree to add node labels to the graphic.

Usage

nodeplotdefault(size=2L, hjust=-0.2)

Arguments

size

(Optional). Numeric. Should be positive. The size parameter used to control the text size of taxa labels. Default is 2. These are ggplot2 sizes.

hjust

(Optional). The horizontal justification of the node labels. Default is -0.2.

Value

A function that can add a node-label layer to a graphic.

See Also

nodeplotboot

nodeplotblank

plot_tree

Examples

nodeplotdefault()
nodeplotdefault(3, -0.4)

Get the number of samples.

Description

Get the number of samples.

Usage

nsamples(physeq)

## S4 method for signature 'ANY'
nsamples(physeq)

## S4 method for signature 'phyloseq'
nsamples(physeq)

## S4 method for signature 'otu_table'
nsamples(physeq)

## S4 method for signature 'sample_data'
nsamples(physeq)

Arguments

physeq

A phyloseq-class, sample_data, or otu_table-class.

Value

An integer indicating the total number of samples.

See Also

taxa_names, sample_names, ntaxa

Examples

#
data("esophagus")
tree <- phy_tree(esophagus)
OTU1 <- otu_table(esophagus)
nsamples(OTU1)
physeq1 <- phyloseq(OTU1, tree)
nsamples(physeq1)

Get the number of taxa/species.

Description

Get the number of taxa/species.

Usage

ntaxa(physeq)

## S4 method for signature 'ANY'
ntaxa(physeq)

## S4 method for signature 'phyloseq'
ntaxa(physeq)

## S4 method for signature 'otu_table'
ntaxa(physeq)

## S4 method for signature 'taxonomyTable'
ntaxa(physeq)

## S4 method for signature 'phylo'
ntaxa(physeq)

## S4 method for signature 'XStringSet'
ntaxa(physeq)

Arguments

physeq

phyloseq-class, otu_table-class, taxonomyTable-class, or phylo

Value

An integer indicating the number of taxa / species.

See Also

taxa_names

Examples

data("esophagus")
ntaxa(esophagus)
phy_tree(esophagus)
ntaxa(phy_tree(esophagus))

Perform an ordination on phyloseq data

Description

This function wraps several commonly-used ordination methods. The type of ordination depends upon the argument to method. Try ordinate("help") or ordinate("list") for the currently supported method options.

Usage

ordinate(physeq, method = "DCA", distance = "bray", formula = NULL,
  ...)

Arguments

physeq

(Required). Phylogenetic sequencing data (phyloseq-class). The data on which you want to perform the ordination. In general, these methods will be based in some fashion on the abundance table ultimately stored as a contingency matrix (otu_table-class). If you're able to import data into phyloseq-class format, than you don't need to worry, as an otu_table is a required component of this class. In addition, some ordination methods require additional data, like a constraining variable or phylogenetic tree. If that is the case, the relevant data should be included in physeq prior to running. Integrating the data in this way also results in these different data components being checked for validity and completeness by the method.

method

(Optional). A character string. Default is "DCA".

Currently supported method options are: c("DCA", "CCA", "RDA", "CAP", "DPCoA", "NMDS", "MDS", "PCoA")

DCA

Performs detrended correspondence analysis usingdecorana

CCA

Performs correspondence analysis, or optionally, constrained correspondence analysis (a.k.a. canonical correspondence analysis), via cca

RDA

Performs redundancy analysis, or optionally principal components analysis, via rda

CAP

[Partial] Constrained Analysis of Principal Coordinates or distance-based RDA, via capscale. See capscale.phyloseq for more details. In particular, a formula argument must be provided.

DPCoA

Performs Double Principle Coordinate Analysis using a (corrected, if necessary) phylogenetic/patristic distance between species. The calculation is performed by DPCoA(), which ultimately uses dpcoa after making the appropriate accessions/corrections of the data.

NMDS

Performs Non-metric MultiDimenstional Scaling of a sample-wise ecological distance matrix onto a user-specified number of axes, k. By default, k=2, but this can be modified as a supplementary argument. This method is ultimately carried out by metaMDS after the appropriate accessions and distance calculations. Because metaMDS includes its own distance calculation wrappers to vegdist, and these provide additional functionality in the form of species scores, ordinate will pass-on the distance argument to metaMDS if it is among the supported vegdist methods. However, all distance methods supported by distance are supported here, including "unifrac" (the default) and "DPCoA".

MDS/PCoA

Performs principal coordinate analysis (also called principle coordinate decomposition, multidimensional scaling (MDS), or classical scaling) of a distance matrix (Gower 1966), including two correction methods for negative eigenvalues. See pcoa for further details.

distance

(Optional). A character string. Default is "bray". The name of a supported distance method; or, alternatively, a pre-computed dist-class object. This argument is only utilized if a distance matrix is required by the ordination method specified by the method argument (above).

Any supported distance methods are supported arguments to distance here. See distance for more details, examples.

formula

(Optional). A model formula. Only relevant for certain ordination methods. The left hand side is ignored, defined by the physeq and distance arguemnts. The right hand side gives the constraining variables, and conditioning variables can be given within a special function Condition. See cca or capscale for examples/details.

...

(Optional). Additional arguments to supporting functions. For example, the additional argument weighted=TRUE would be passed on to UniFrac if "unifrac" were chosen as the distance option and "MDS" as the ordination method option. Alternatively, if "DCA" were chosen as the ordination method option, additional arguments would be passed on to the relevant ordination function, decorana, for example.

Value

An ordination object. The specific class of the returned object depends upon the ordination method, as well as the function/package that is called internally to perform it. As a general rule, any of the ordination classes returned by this function will be recognized by downstream tools in the phyloseq package, for example the ordination plotting function, plot_ordination.

See Also

The plot_ordination Tutorial

Related component ordination functions described within phyloseq:

DPCoA

Described/provided by other packages:

cca/rda, decorana, metaMDS, pcoa, capscale

NMDS and MDS/PCoA both operate on distance matrices, typically based on some pairwise comparison of the microbiomes in an experiment/project. There are a number of common methods to use to calculate these pairwise distances, and the most convenient function (from a phyloseq point of view) for calculating these distance matrices is the

distance

function. It can be thought of as a distance / dissimilarity-index companion function for ordinate, and indeed the distance options provided to ordinate are often simply passed on to distance.

A good quick summary of ordination is provided in the introductory vignette for vegan:

vegan introductory vignette

The following R task views are also useful for understanding the available tools in R:

Analysis of Ecological and Environmental Data

Multivariate Statistics

Examples

# See http://joey711.github.io/phyloseq/plot_ordination-examples
# for many more examples.
# plot_ordination(GP, ordinate(GP, "DCA"), "samples", color="SampleType")

Build or access the otu_table.

Description

This is the suggested method for both constructing and accessing Operational Taxonomic Unit (OTU) abundance (otu_table-class) objects. When the first argument is a matrix, otu_table() will attempt to create and return an otu_table-class object, which further depends on whether or not taxa_are_rows is provided as an additional argument. Alternatively, if the first argument is an experiment-level (phyloseq-class) object, then the corresponding otu_table is returned.

Usage

otu_table(object, taxa_are_rows, errorIfNULL=TRUE)

## S4 method for signature 'phyloseq'
otu_table(object, errorIfNULL = TRUE)

## S4 method for signature 'otu_table'
otu_table(object, errorIfNULL = TRUE)

## S4 method for signature 'matrix'
otu_table(object, taxa_are_rows)

## S4 method for signature 'data.frame'
otu_table(object, taxa_are_rows)

## S4 method for signature 'ANY'
otu_table(object, errorIfNULL = TRUE)

Arguments

object

(Required). An integer matrix, otu_table-class, or phyloseq-class.

taxa_are_rows

(Conditionally optional). Logical; of length 1. Ignored unless object is a matrix, in which case it is is required.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE. Ignored if object argument is a matrix (constructor invoked instead).

Value

An otu_table-class object.

See Also

phy_tree, sample_data, tax_table phyloseq, merge_phyloseq

Examples

#
# data(GlobalPatterns)
# otu_table(GlobalPatterns)

The S4 class for storing taxa-abundance information.

Description

Because orientation of these tables can vary by method, the orientation is defined explicitly in the taxa_are_rows slot (a logical). The otu_table class inherits the matrix class to store abundance values. Various standard subset and assignment nomenclature has been extended to apply to the otu_table class, including square-bracket, t, etc.

Details

taxa_are_rows

A single logical specifying the orientation of the abundance table.

.Data

This slot is inherited from the matrix class.


Assign a new OTU Table to x

Description

Assign a new OTU Table to x

Usage

otu_table(x) <- value

## S4 replacement method for signature 'phyloseq,otu_table'
otu_table(x) <- value

## S4 replacement method for signature 'otu_table,otu_table'
otu_table(x) <- value

## S4 replacement method for signature 'phyloseq,phyloseq'
otu_table(x) <- value

Arguments

x

(Required). phyloseq-class

value

(Required). otu_table-class or phyloseq-class.

Examples

# data(GlobalPatterns)
# # An example of pruning to just the first 100 taxa in GlobalPatterns.
# ex2a <- prune_taxa(taxa_names(GlobalPatterns)[1:100], GlobalPatterns)
# # The following 3 lines produces an ex2b that is equal to ex2a
# ex2b <- GlobalPatterns
# OTU <- otu_table(GlobalPatterns)[1:100, ]
# otu_table(ex2b) <- OTU
# identical(ex2a, ex2b)
# print(ex2b)
# # Relace otu_table by implying the component in context.
# ex2c <- GlobalPatterns
# otu_table(ex2c) <- ex2b
# identical(ex2a, ex2c)

Parse elements of a taxonomy vector

Description

These are provided as both example and default functions for parsing a character vector of taxonomic rank information for a single taxa. As default functions, these are intended for cases where the data adheres to the naming convention used by greengenes (http://greengenes.lbl.gov/cgi-bin/nph-index.cgi) or where the convention is unknown, respectively. To work, these functions – and any similar custom function you may want to create and use – must take as input a single character vector of taxonomic ranks for a single OTU, and return a named character vector that has been modified appropriately (according to known naming conventions, desired length limits, etc. The length (number of elements) of the output named vector does not need to be equal to the input, which is useful for the cases where the source data files have extra meaningless elements that should probably be removed, like the ubiquitous “Root” element often found in greengenes/QIIME taxonomy labels. In the case of parse_taxonomy_default, no naming convention is assumed and so dummy rank names are added to the vector. More usefully if your taxonomy data is based on greengenes, the parse_taxonomy_greengenes function clips the first 3 characters that identify the rank, and uses these to name the corresponding element according to the appropriate taxonomic rank name used by greengenes (e.g. "p__" at the beginning of an element means that element is the name of the phylum to which this OTU belongs). Most importantly, the expectations for these functions described above make them compatible to use during data import, specifcally the import_biom function, but it is a flexible structure that will be implemented soon for all phyloseq import functions that deal with taxonomy (e.g. import_qiime).

Usage

parse_taxonomy_default(char.vec)

parse_taxonomy_greengenes(char.vec)

parse_taxonomy_qiime(char.vec)

Arguments

char.vec

(Required). A single character vector of taxonomic ranks for a single OTU, unprocessed (ugly).

Value

A character vector in which each element is a different taxonomic rank of the same OTU, and each element name is the name of the rank level. For example, an element might be "Firmicutes" and named "phylum". These parsed, named versions of the taxonomic vector should reflect embedded information, naming conventions, desired length limits, etc; or in the case of parse_taxonomy_default, not modified at all and given dummy rank names to each element.

See Also

import_biom import_qiime

Examples

taxvec1 = c("Root", "k__Bacteria", "p__Firmicutes", "c__Bacilli", "o__Bacillales", "f__Staphylococcaceae")
 parse_taxonomy_default(taxvec1)
 parse_taxonomy_greengenes(taxvec1)
 taxvec2 = c("Root;k__Bacteria;p__Firmicutes;c__Bacilli;o__Bacillales;f__Staphylococcaceae")
 parse_taxonomy_qiime(taxvec2)

Retrieve phylogenetic tree (phylo-class) from object.

Description

This is the suggested method for accessing the phylogenetic tree, (phylo-class) from a phyloseq-class. Like other accessors (see See Also, below), the default behavior of this method is to stop with an error if physeq is a phyloseq-class but does not contain a phylogenetic tree (the component data you are trying to access in this case).

Usage

phy_tree(physeq, errorIfNULL=TRUE)

## S4 method for signature 'ANY'
phy_tree(physeq, errorIfNULL = TRUE)

## S4 method for signature 'phylo'
phy_tree(physeq)

Arguments

physeq

(Required). An instance of phyloseq-class that contains a phylogenetic tree. If physeq is a phylogenetic tree (a component data class), then it is returned as-is.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE.

Details

Note that the tip labels should be named to match the taxa_names of the other objects to which it is going to be paired. The phyloseq constructor automatically checks for exact agreement in the set of species described by the phlyogenetic tree and the other components (taxonomyTable, otu_table), and trims as-needed. Thus, the tip.labels in a phylo object must be named to match the results of taxa_names of the other objects to which it will ultimately be paired.

Value

The phylo-class object contained within physeq; or NULL if physeq does not have a tree. This method stops with an error in the latter NULL case be default, which can be over-ridden by changing the value of errorIfNULL to FALSE.

See Also

otu_table, sample_data, tax_table refseq, phyloseq, merge_phyloseq

Examples

data(GlobalPatterns)
 phy_tree(GlobalPatterns)

Assign a (new) phylogenetic tree to x

Description

Assign a (new) phylogenetic tree to x

Usage

phy_tree(x) <- value

## S4 replacement method for signature 'phyloseq,phylo'
phy_tree(x) <- value

## S4 replacement method for signature 'phyloseq,phyloseq'
phy_tree(x) <- value

Arguments

x

(Required). phyloseq-class

value

(Required). phylo-class, or phyloseq-class

Examples

#
data("esophagus")
# An example of pruning to just the first 20 taxa in esophagus
ex2a <- prune_taxa(taxa_names(esophagus)[1:20], esophagus)
# The following 3 lines produces an ex2b that is equal to ex2a
ex2b <- ex2a
phy_tree(ex2b) <- phy_tree(esophagus)
identical(ex2a, ex2b)

An S4 placeholder of the main phylogenetic tree class from the ape package.

Description

See the ape package for details about this type of representation of a phylogenetic tree. It is used throughout the ape package.

See Also

phylo, setOldClass


Build phyloseq-class objects from their components.

Description

phyloseq() is a constructor method, This is the main method suggested for constructing an experiment-level (phyloseq-class) object from its component data (component data classes: otu_table-class, sample_data-class, taxonomyTable-class, phylo-class).

Usage

phyloseq(...)

Arguments

...

One or more component objects among the set of classes defined by the phyloseq package, as well as phylo-class (defined by the ape-package). Each argument should be a different class. For combining multiple components of the same class, or multiple phyloseq-class objects, use the merge_phyloseq function. Unlike in earlier versions, the arguments to phyloseq do not need to be named, and the order of the arguments does not matter.

Value

The class of the returned object depends on the argument class(es). For an experiment-level object, two or more component data objects must be provided. Otherwise, if a single component-class is provided, it is simply returned as-is. The order of arguments does not matter.

See Also

merge_phyloseq

Examples

data(esophagus)
x1 = phyloseq(otu_table(esophagus), phy_tree(esophagus))
identical(x1, esophagus)
# # data(GlobalPatterns)
# # GP <- GlobalPatterns
# # phyloseq(sample_data(GP), otu_table(GP))
# # phyloseq(otu_table(GP), phy_tree(GP))
# # phyloseq(tax_table(GP), otu_table(GP))
# # phyloseq(phy_tree(GP), otu_table(GP), sample_data(GP))
# # phyloseq(otu_table(GP), tax_table(GP), sample_data(GP))
# # phyloseq(otu_table(GP), phy_tree(GP), tax_table(GP), sample_data(GP))

Convert phyloseq data to DESeq2 dds object

Description

No testing is performed by this function. The phyloseq data is converted to the relevant DESeqDataSet object, which can then be tested in the negative binomial generalized linear model framework of the DESeq function in DESeq2 package. See the phyloseq-extensions tutorials for more details.

Usage

phyloseq_to_deseq2(physeq, design, ...)

Arguments

physeq

(Required). phyloseq-class. Must have a sample_data component.

design

(Required). A formula which specifies the design of the experiment, taking the form formula(~ x + y + z). That is, a formula with right-hand side only. By default, the functions in this package and DESeq2 will use the last variable in the formula (e.g. z) for presenting results (fold changes, etc.) and plotting. When considering your specification of experimental design, you will want to re-order the levels so that the NULL set is first. For example, the following line of code would ensure that Enterotype 1 is used as the reference sample class in tests by setting it to the first of the factor levels using the relevel function:

sample_data(entill)$Enterotype <- relevel(sample_data(entill)$Enterotype, "1")

...

(Optional). Additional named arguments passed to DESeqDataSetFromMatrix. Most users will not need to pass any additional arguments here. Most testing-related options should be provided in a following call to DESeq.

Value

A DESeqDataSet object.

See Also

vignette("phyloseq-mixture-models")

The phyloseq-extensions tutorials.

DESeq

results

DESeqDataSetFromMatrix

Examples

# Check out the vignette phyloseq-mixture-models for more details.
 # vignette("phyloseq-mixture-models")
 data(soilrep)
 phyloseq_to_deseq2(soilrep, ~warmed)

Convert phyloseq data to MetagenomeSeq MRexperiment object

Description

No testing is performed by this function. The phyloseq data is converted to the relevant MRexperiment-class object, which can then be tested in the zero-inflated mixture model framework (e.g. fitZig) in the metagenomeSeq package. See the phyloseq-extensions tutorials for more details.

Usage

phyloseq_to_metagenomeSeq(physeq, ...)

Arguments

physeq

(Required). phyloseq-class.

...

(Optional). Additional named arguments passed to newMRexperiment. Most users will not need to pass any additional arguments here.

Value

A MRexperiment-class object.

See Also

fitTimeSeries fitLogNormal fitZig MRtable MRfulltable

Examples

# Check out the vignette metagenomeSeq for more details.
 # vignette("metagenomeSeq")
 data(soilrep)
 phyloseq_to_metagenomeSeq(soilrep)

The main experiment-level class for phyloseq data

Description

Contains all currently-supported component data classes: otu_table-class, sample_data-class, taxonomyTable-class ("tax_table" slot), phylo-class ("phy_tree" slot), and the XStringSet-class ("refseq" slot). There are several advantages to storing your phylogenetic sequencing experiment as an instance of the phyloseq class, not the least of which is that it is easy to return to the data later and feel confident that the different data types “belong” to one another. Furthermore, the phyloseq constructor ensures that the different data components have compatible indices (e.g. OTUs and samples), and performs the necessary trimming automatically when you create your “experiment-level” object. Downstream analyses are aware of which data classes they require – and where to find them – often making your phyloseq-class object the only data argument required for analysis and plotting functions (although there are many options and parameter arguments available to you).

Details

In the case of missing component data, the slots are set to NULL. As soon as a phyloseq-class object is to be updated with new component data (previously missing/NULL or not), the indices of all components are re-checked for compatibility and trimmed if necessary. This is to ensure by design that components describe the same taxa/samples, and also that these trimming/validity checks do not need to be repeated in downstream analyses.

slots:

otu_table

a single object of class otu_table.

sam_data

a single object of class sample_data.

tax_table

a single object of class taxonomyTable.

phy_tree

a single object of the phylo-class, from the ape package.

refseq

a biological sequence set object of a class that inherits from the XStringSet-class, from the Biostrings package.

See Also

The constructor, phyloseq, the merger merge_phyloseq, and also the component constructor/accessors otu_table, sample_data, tax_table, phy_tree, and refseq.


Depcrecated functions in the phyloseq package.

Description

These will be migrated to "defunct" status in the next release, and removed completely in the release after that. These functions are provided for compatibility with older version of the phyloseq package. They may eventually be completely removed.

Usage

deprecated_phyloseq_function(x, value, ...)

Arguments

x

For assignment operators, the object that will undergo a replacement (object inside parenthesis).

value

For assignment operators, the value to replace with (the right side of the assignment).

...

For functions other than assignment operators, parameters to be passed to the modern version of the function (see table).

Details

plot_taxa_bar now a synonym for plot_bar
taxaplot now a synonym for plot_bar
taxtab now a synonym for tax_table
taxTab now a synonym for tax_table
sampleData now a synonym for sample_data
samData now a synonym for sample_data
sam_data now a synonym for sample_data
speciesSums now a synonym for taxa_sums
sampleSums now a synonym for sample_sums
nspecies now a synonym for ntaxa
species.names now a synonym for taxa_names
sampleNames now a synonym for sample_names
sample.names now a synonym for sample_names
getSamples now a synonym for get_sample
getSpecies now a synonym for get_taxa
rank.names now a synonym for rank_names
getTaxa now a synonym for get_taxa_unique
sample.variables now a synonym for sample_variables
getVariable now a synonym for get_variable
merge_species now a synonym for merge_taxa
otuTable now a synonym for otu_table
speciesarerows now a synonym for taxa_are_rows
speciesAreRows now a synonym for taxa_are_rows
plot_richness_estimates now a synonym for plot_richness
import_qiime_sampleData now a synonym for import_qiime_sample_data
filterfunSample now a synonym for filterfun_sample
genefilterSample now a synonym for genefilter_sample
prune_species now a synonym for prune_taxa
subset_species now a synonym for subset_taxa
tipglom now a synonym for tip_glom
taxglom now a synonym for tax_glom
tre now a synonym for phy_tree
show_mothur_list_cutoffs now a synonym for show_mothur_cutoffs
sam_data<- now a synonym for sample_data<-
sampleData<- now a synonym for sample_data<-
tre<- now a synonym for phy_tree<-
speciesAreRows<- now a synonym for taxa_are_rows<-
otuTable<- now a synonym for otu_table<-
taxTab<- now a synonym for tax_table<-

A flexible, informative barplot phyloseq data

Description

There are many useful examples of phyloseq barplot graphics in the phyloseq online tutorials. This function wraps ggplot2 plotting, and returns a ggplot2 graphic object that can be saved or further modified with additional layers, options, etc. The main purpose of this function is to quickly and easily create informative summary graphics of the differences in taxa abundance between samples in an experiment.

Usage

plot_bar(physeq, x="Sample", y="Abundance", fill=NULL,
 title=NULL, facet_grid=NULL)

Arguments

physeq

(Required). An otu_table-class or phyloseq-class.

x

(Optional). Optional, but recommended, especially if your data is comprised of many samples. A character string. The variable in the melted-data that should be mapped to the x-axis. See psmelt, melt, and ggplot for more details.

y

(Optional). A character string. The variable in the melted-data that should be mapped to the y-axis. Typically this will be "Abundance", in order to quantitatively display the abundance values for each OTU/group. However, alternative variables could be used instead, producing a very different, though possibly still informative, plot. See psmelt, melt, and ggplot for more details.

fill

(Optional). A character string. Indicates which sample variable should be used to map to the fill color of the bars. The default is NULL, resulting in a gray fill for all bar segments.

title

(Optional). Default NULL. Character string. The main title for the graphic.

facet_grid

(Optional). A formula object. It should describe the faceting you want in exactly the same way as for facet_grid, and is ulitmately provided to ggplot2 graphics. The default is: NULL, resulting in no faceting.

Value

A ggplot2 graphic object – rendered in the graphical device as the default print/show method.

See Also

phyloseq online tutorials.

psmelt

ggplot

qplot

Examples

data("GlobalPatterns")
gp.ch = subset_taxa(GlobalPatterns, Phylum == "Chlamydiae")
plot_bar(gp.ch)
plot_bar(gp.ch, fill="Genus")
plot_bar(gp.ch, x="SampleType", fill="Genus")
plot_bar(gp.ch, "SampleType", fill="Genus", facet_grid=~Family)
# See additional examples in the plot_bar online tutorial. Link above.

Create a ggplot summary of gap statistic results

Description

Create a ggplot summary of gap statistic results

Usage

plot_clusgap(clusgap, title = "Gap Statistic results")

Arguments

clusgap

(Required). An object of S3 class "clusGap", basically a list with components. See the clusGap documentation for more details. In most cases this will be the output of gapstat_ord, or clusGap if you called it directly.

title

(Optional). Character string. The main title for the graphic. Default is "Gap Statistic results".

Value

A ggplot plot object. The rendered graphic should be a plot of the gap statistic score versus values for k, the number of clusters.

See Also

gapstat_ord

clusGap

ggplot

Examples

# Load and process data
data("soilrep")
soilr = rarefy_even_depth(soilrep, rngseed=888)
print(soilr)
sample_variables(soilr)
# Ordination
sord  = ordinate(soilr, "DCA")
# Gap Statistic
gs = gapstat_ord(sord, axes=1:4, verbose=FALSE)
# Evaluate results with plots, etc.
plot_scree(sord)
plot_ordination(soilr, sord,  color="Treatment")
plot_clusgap(gs)
print(gs, method="Tibs2001SEmax")
# Non-ordination example, use cluster::clusGap function directly
library("cluster")
pam1 = function(x, k){list(cluster = pam(x, k, cluster.only=TRUE))}
gs.pam.RU = clusGap(ruspini, FUN = pam1, K.max = 8, B = 60)
gs.pam.RU
plot(gs.pam.RU, main = "Gap statistic for the 'ruspini' data")
mtext("k = 4 is best .. and  k = 5  pretty close")
plot_clusgap(gs.pam.RU)

Create an ecologically-organized heatmap using ggplot2 graphics

Description

There are many useful examples of phyloseq heatmap graphics in the phyloseq online tutorials. In a 2010 article in BMC Genomics, Rajaram and Oono show describe an approach to creating a heatmap using ordination methods to organize the rows and columns instead of (hierarchical) cluster analysis. In many cases the ordination-based ordering does a much better job than h-clustering. An immediately useful example of their approach is provided in the NeatMap package for R. The NeatMap package can be used directly on the abundance table (otu_table-class) of phylogenetic-sequencing data, but the NMDS or PCA ordination options that it supports are not based on ecological distances. To fill this void, phyloseq provides the plot_heatmap() function as an ecology-oriented variant of the NeatMap approach to organizing a heatmap and build it using ggplot2 graphics tools. The distance and method arguments are the same as for the plot_ordination function, and support large number of distances and ordination methods, respectively, with a strong leaning toward ecology. This function also provides the options to re-label the OTU and sample axis-ticks with a taxonomic name and/or sample variable, respectively, in the hope that this might hasten your interpretation of the patterns (See the sample.label and taxa.label documentation, below). Note that this function makes no attempt to overlay hierarchical clustering trees on the axes, as hierarchical clustering is not used to organize the plot. Also note that each re-ordered axis repeats at the edge, and so apparent clusters at the far right/left or top/bottom of the heat-map may actually be the same. For now, the placement of this edge can be considered arbitrary, so beware of this artifact of this graphical representation. If you benefit from this phyloseq-specific implementation of the NeatMap approach, please cite both our packages/articles.

Usage

plot_heatmap(physeq, method = "NMDS", distance = "bray",
  sample.label = NULL, taxa.label = NULL, low = "#000033",
  high = "#66CCFF", na.value = "black", trans = log_trans(4),
  max.label = 250, title = NULL, sample.order = NULL,
  taxa.order = NULL, first.sample = NULL, first.taxa = NULL, ...)

Arguments

physeq

(Required). The data, in the form of an instance of the phyloseq-class. This should be what you get as a result from one of the import functions, or any of the processing downstream. No data components beyond the otu_table are strictly necessary, though they may be useful if you want to re-label the axis ticks according to some observable or taxonomic rank, for instance, or if you want to use a UniFrac-based distance (in which case your physeq data would need to have a tree included).

method

(Optional). The ordination method to use for organizing the heatmap. A great deal of the usefulness of a heatmap graphic depends upon the way in which the rows and columns are ordered.

distance

(Optional). A character string. The ecological distance method to use in the ordination. See distance.

sample.label

(Optional). A character string. The sample variable by which you want to re-label the sample (horizontal) axis.

taxa.label

(Optional). A character string. The name of the taxonomic rank by which you want to re-label the taxa/species/OTU (vertical) axis. You can see available options in your data using rank_names(physeq).

low

(Optional). A character string. An R color. See ?colors for options support in R (there are lots). The color that represents the lowest non-zero value in the heatmap. Default is a dark blue color, "#000033".

high

(Optional). A character string. An R color. See colors for options support in R (there are lots). The color that will represent the highest value in the heatmap. The default is "#66CCFF". Zero-values are treated as NA, and set to "black", to represent a background color.

na.value

(Optional). A character string. An R color. See colors for options support in R (there are lots). The color to represent what is essentially the background of the plot, the non-observations that occur as NA or 0 values in the abundance table. The default is "black", which works well on computer-screen graphics devices, but may be a poor choice for printers, in which case you might want this value to be "white", and reverse the values of high and low, above.

trans

(Optional). "trans"-class transformer-definition object. A numerical transformer to use in the continuous color scale. See trans_new for details. The default is log_trans(4).

max.label

(Optional). Integer. Default is 250. The maximum number of labeles to fit on a given axis (either x or y). If number of taxa or samples exceeds this value, the corresponding axis will be stripped of any labels.

This supercedes any arguments provided to sample.label or taxa.label. Make sure to increase this value if, for example, you want a special label for an axis that has 300 indices.

title

(Optional). Default NULL. Character string. The main title for the graphic.

sample.order

(Optional). Default NULL. Either a single character string matching one of the sample_variables in your data, or a character vector of sample_names in the precise order that you want them displayed in the heatmap. This overrides any ordination ordering that might be done with the method/distance arguments.

taxa.order

(Optional). Default NULL. Either a single character string matching one of the rank_names in your data, or a character vector of taxa_names in the precise order that you want them displayed in the heatmap. This overrides any ordination ordering that might be done with the method/distance arguments.

first.sample

(Optional). Default NULL. A character string matching one of the sample_names of your input data (physeq). It will become the left-most sample in the plot. For the ordination-based ordering (recommended), the left and right edges of the axes are adjaacent in a continuous ordering. Therefore, the choice of starting sample is meaningless and arbitrary, but it is aesthetically poor to have the left and right edge split a natural cluster in the data. This argument allows you to specify the left edge and thereby avoid cluster-splitting, emphasize a gradient, etc.

first.taxa

(Optional). Default NULL. A character string matching one of the taxa_names of your input data (physeq). This is equivalent to first.sample (above), but for the taxa/OTU indices, usually the vertical axis.

...

(Optional). Additional parameters passed to ordinate.

Details

This approach borrows heavily from the heatmap1 function in the NeatMap package. Highly recommended, and we are grateful for their package and ideas, which we have adapted for our specific purposes here, but did not use an explicit dependency. At the time of the first version of this implementation, the NeatMap package depends on the rgl-package, which is not needed in phyloseq, at present. Although likely a transient issue, the rgl-package has some known installation issues that have further influenced to avoid making NeatMap a formal dependency (Although we love both NeatMap and rgl!).

Value

A heatmap plot, in the form of a ggplot2 plot object, which can be further saved and modified.

References

Because this function relies so heavily in principle, and in code, on some of the functionality in NeatMap, please site their article if you use this function in your work.

Rajaram, S., & Oono, Y. (2010). NeatMap–non-clustering heat map alternatives in R. BMC Bioinformatics, 11, 45.

Please see further examples in the phyloseq online tutorials.

Examples

data("GlobalPatterns")
gpac <- subset_taxa(GlobalPatterns, Phylum=="Crenarchaeota")
# FYI, the base-R function uses a non-ecological ordering scheme,
# but does add potentially useful hclust dendrogram to the sides...
gpac <- subset_taxa(GlobalPatterns, Phylum=="Crenarchaeota")
# Remove the nearly-empty samples (e.g. 10 reads or less)
gpac = prune_samples(sample_sums(gpac) > 50, gpac)
# Arbitrary order if method set to NULL
plot_heatmap(gpac, method=NULL, sample.label="SampleType", taxa.label="Family")
# Use ordination
plot_heatmap(gpac, sample.label="SampleType", taxa.label="Family")
# Use ordination for OTUs, but not sample-order
plot_heatmap(gpac, sample.label="SampleType", taxa.label="Family", sample.order="SampleType")
# Specifying both orders omits any attempt to use ordination. The following should be the same.
p0 = plot_heatmap(gpac, sample.label="SampleType", taxa.label="Family", taxa.order="Phylum", sample.order="SampleType")
p1 = plot_heatmap(gpac, method=NULL, sample.label="SampleType", taxa.label="Family", taxa.order="Phylum", sample.order="SampleType")
#expect_equivalent(p0, p1)
# Example: Order matters. Random ordering of OTU indices is difficult to interpret, even with structured sample order
rando = sample(taxa_names(gpac), size=ntaxa(gpac), replace=FALSE)
plot_heatmap(gpac, method=NULL, sample.label="SampleType", taxa.label="Family", taxa.order=rando, sample.order="SampleType")
# # Select the edges of each axis. 
# First, arbitrary edge, ordering
plot_heatmap(gpac, method=NULL)
# Second, biological-ordering (instead of default ordination-ordering), but arbitrary edge
plot_heatmap(gpac, taxa.order="Family", sample.order="SampleType")
# Third, biological ordering, selected edges
plot_heatmap(gpac, taxa.order="Family", sample.order="SampleType", first.taxa="546313", first.sample="NP2")
# Fourth, add meaningful labels
plot_heatmap(gpac, sample.label="SampleType", taxa.label="Family", taxa.order="Family", sample.order="SampleType", first.taxa="546313", first.sample="NP2")

Microbiome Network Plot using ggplot2

Description

There are many useful examples of phyloseq network graphics in the phyloseq online tutorials. A custom plotting function for displaying networks using advanced ggplot2 formatting. Note that this function is a performance and interface revision to plot_network, which requires an igraph object as its first argument. This new function is more in-line with other plot_* functions in the phyloseq-package, in that its first/main argument is a phyloseq-class instance. Edges in the network are created if the distance between nodes is below a (potentially arbitrary) threshold, and special care should be given to considering the choice of this threshold. However, network line thickness and opacity is scaled according to the similarity of vertices (either samples or taxa), helping to temper, somewhat, the effect of the threshold. Also note that the choice of network layout algorithm can have a large effect on the impression and interpretability of the network graphic, and you may want to familiarize yourself with some of these options (see the laymeth argument).

Usage

plot_net(physeq, distance = "bray", type = "samples", maxdist = 0.7,
  laymeth = "fruchterman.reingold", color = NULL, shape = NULL,
  rescale = FALSE, point_size = 5, point_alpha = 1,
  point_label = NULL, hjust = 1.35, title = NULL)

Arguments

physeq

(Required). The phyloseq-class object that you want to represent as a network.

distance

(Optional). Default is "bray". Can be either a distance method supported by distance, or an already-computed dist-class with labels that match the indices implied by both the physeq and type arguments (that is, either sample or taxa names). If you used distance to pre-calculate your distance, and the same type argument as provided here, then they will match.

type

(Optional). Default "samples". Whether the network represented in the primary argument, g, is samples or taxa/OTUs. Supported arguments are "samples", "taxa", where "taxa" indicates using the taxa indices, whether they actually represent species or some other taxonomic rank.

maxdist

(Optional). Default 0.7. The maximum distance value between two vertices to connect with an edge in the graphic.

laymeth

(Optional). Default "fruchterman.reingold". A character string that indicates the method that will determine the placement of vertices, typically based on conectedness of vertices and the number of vertices. This is an interesting topic, and there are lots of options. See igraph-package for related topics in general, and see layout.auto for descriptions of various alternative layout method options supported here. The character string argument should match exactly the layout function name with the "layout." omitted. Try laymeth="list" to see a list of options.

color

(Optional). Default NULL. The name of the sample variable in physeq to use for color mapping of points (graph vertices).

shape

(Optional). Default NULL. The name of the sample variable in physeq to use for shape mapping. of points (graph vertices).

rescale

(Optional). Logical. Default FALSE. Whether to rescale the distance values to be [0, 1], in which the min value is close to zero and the max value is 1.

point_size

(Optional). Default 5. The size of the vertex points.

point_alpha

(Optional). Default 1. A value between 0 and 1 for the alpha transparency of the vertex points.

point_label

(Optional). Default NULL. The variable name in physeq covariate data to map to vertex labels.

hjust

(Optional). Default 1.35. The amount of horizontal justification to use for each label.

title

(Optional). Default NULL. Character string. The main title for the graphic.

Value

A ggplot2 network plot. Will render to default graphic device automatically as print side effect. Can also be saved, further manipulated, or rendered to a vector or raster file using ggsave.

See Also

Original network plotting functions:

make_network

plot_network

Examples

data(enterotype)
plot_net(enterotype, color="SeqTech", maxdist = 0.3)
plot_net(enterotype, color="SeqTech", maxdist = 0.3, laymeth = "auto")
plot_net(enterotype, color="SeqTech", maxdist = 0.3, laymeth = "svd")
plot_net(enterotype, color="SeqTech", maxdist = 0.3, laymeth = "circle")
plot_net(enterotype, color="SeqTech", shape="Enterotype", maxdist = 0.3, laymeth = "circle")

Microbiome Network Plot using ggplot2

Description

There are many useful examples of phyloseq network graphics in the phyloseq online tutorials. A custom plotting function for displaying networks using advanced ggplot2 formatting. The network itself should be represented using the igraph package. For the phyloseq-package it is suggested that the network object (argument g) be created using the make_network function, and based upon sample-wise or taxa-wise microbiome ecological distances calculated from a phylogenetic sequencing experiment (phyloseq-class). In this case, edges in the network are created if the distance between nodes is below a potentially arbitrary threshold, and special care should be given to considering the choice of this threshold.

Usage

plot_network(g, physeq=NULL, type="samples", 
	color=NULL, shape=NULL, point_size=4, alpha=1,
	label="value", hjust = 1.35, 
	line_weight=0.5, line_color=color, line_alpha=0.4,
	layout.method=layout.fruchterman.reingold, title=NULL)

Arguments

g

(Required). An igraph-class object created either by the convenience wrapper make_network, or directly by the tools in the igraph-package.

physeq

(Optional). Default NULL. A phyloseq-class object on which g is based.

type

(Optional). Default "samples". Whether the network represented in the primary argument, g, is samples or taxa/OTUs. Supported arguments are "samples", "taxa", where "taxa" indicates using the taxa indices, whether they actually represent species or some other taxonomic rank.

color

(Optional). Default NULL. The name of the sample variable in physeq to use for color mapping of points (graph vertices).

shape

(Optional). Default NULL. The name of the sample variable in physeq to use for shape mapping. of points (graph vertices).

point_size

(Optional). Default 4. The size of the vertex points.

alpha

(Optional). Default 1. A value between 0 and 1 for the alpha transparency of the vertex points.

label

(Optional). Default "value". The name of the sample variable in physeq to use for labelling the vertex points.

hjust

(Optional). Default 1.35. The amount of horizontal justification to use for each label.

line_weight

(Optional). Default 0.3. The line thickness to use to label graph edges.

line_color

(Optional). Default color. The name of the sample variable in physeq to use for color mapping of lines (graph edges).

line_alpha

(Optional). Default 0.4. The transparency level for graph-edge lines.

layout.method

(Optional). Default layout.fruchterman.reingold. A function (closure) that determines the placement of the vertices for drawing a graph. Should be able to take an igraph-class as sole argument, and return a two-column coordinate matrix with nrow equal to the number of vertices. For possible options already included in igraph-package, see the others also described in the help file:

title

(Optional). Default NULL. Character string. The main title for the graphic.

layout.fruchterman.reingold

Value

A ggplot2 plot representing the network, with optional mapping of variable(s) to point color or shape.

References

This code was adapted from a repo original hosted on GitHub by Scott Chamberlain: https://github.com/SChamberlain/gggraph

The code most directly used/modified was first posted here: http://www.r-bloggers.com/basic-ggplot2-network-graphs/

See Also

make_network

Examples

data(enterotype)
ig <- make_network(enterotype, max.dist=0.3)
plot_network(ig, enterotype, color="SeqTech", shape="Enterotype", line_weight=0.3, label=NULL)
# Change distance parameter
ig <- make_network(enterotype, max.dist=0.2)
plot_network(ig, enterotype, color="SeqTech", shape="Enterotype", line_weight=0.3, label=NULL)

General ordination plotter based on ggplot2.

Description

There are many useful examples of phyloseq ordination graphics in the phyloseq online tutorials. Convenience wrapper for plotting ordination results as a ggplot2-graphic, including additional annotation in the form of shading, shape, and/or labels of sample variables.

Usage

plot_ordination(physeq, ordination, type = "samples", axes = 1:2,
  color = NULL, shape = NULL, label = NULL, title = NULL,
  justDF = FALSE)

Arguments

physeq

(Required). phyloseq-class. The data about which you want to plot and annotate the ordination.

ordination

(Required). An ordination object. Many different classes of ordination are defined by R packages. Ordination classes currently supported/created by the ordinate function are supported here. There is no default, as the expectation is that the ordination will be performed and saved prior to calling this plot function.

type

(Optional). The plot type. Default is "samples". The currently supported options are c("samples", "sites", "species", "taxa", "biplot", "split", "scree"). The option “taxa” is equivalent to “species” in this case, and similarly, “samples” is equivalent to “sites”. The options "sites" and "species" result in a single-plot of just the sites/samples or species/taxa of the ordination, respectively. The "biplot" and "split" options result in a combined plot with both taxa and samples, either combined into one plot (“biplot”) or separated in two facet panels (“split”), respectively. The "scree" option results in a call to plot_scree, which produces an ordered bar plot of the normalized eigenvalues associated with each ordination axis.

axes

(Optional). A 2-element vector indicating the axes of the ordination that should be used for plotting. Can be character-class or integer-class, naming the index name or index of the desired axis for the horizontal and vertical axes, respectively, in that order. The default value, c(1, 2), specifies the first two axes of the provided ordination.

color

(Optional). Default NULL. Character string. The name of the variable to map to colors in the plot. This can be a sample variable (among the set returned by sample_variables(physeq) ) or taxonomic rank (among the set returned by rank_names(physeq)).

Note that the color scheme is chosen automatically by link{ggplot}, but it can be modified afterward with an additional layer using scale_color_manual.

shape

(Optional). Default NULL. Character string. The name of the variable to map to different shapes on the plot. Similar to color option, but for the shape if points.

The shape scale is chosen automatically by link{ggplot}, but it can be modified afterward with an additional layer using scale_shape_manual.

label

(Optional). Default NULL. Character string. The name of the variable to map to text labels on the plot. Similar to color option, but for plotting text.

title

(Optional). Default NULL. Character string. The main title for the graphic.

justDF

(Optional). Default FALSE. Logical. Instead of returning a ggplot2-object, do you just want the relevant data.frame that was used to build the plot? This is a user-accessible option for obtaining the data.frame, in in principal to make a custom plot that isn't possible with the available options in this function. For contributing new functions (developers), the phyloseq-package provides/uses an internal function to build the key features of the data.frame prior to plot-build.

Value

A ggplot plot object, graphically summarizing the ordination result for the specified axes.

See Also

Many more examples are included in the phyloseq online tutorials.

Also see the general wrapping function:

plot_phyloseq

Examples

# See other examples at
# http://joey711.github.io/phyloseq/plot_ordination-examples
data(GlobalPatterns)
GP = prune_taxa(names(sort(taxa_sums(GlobalPatterns), TRUE)[1:50]), GlobalPatterns)
gp_bray_pcoa = ordinate(GP, "CCA", "bray")
plot_ordination(GP, gp_bray_pcoa, "samples", color="SampleType")

Generic plot defaults for phyloseq.

Description

There are many useful examples of phyloseq graphics functions in the phyloseq online tutorials. The specific plot type is chosen according to available non-empty slots. This is mainly for syntactic convenience and quick-plotting. See links below for some examples of available graphics tools available in the phyloseq-package.

Usage

plot_phyloseq(physeq, ...)

## S4 method for signature 'phyloseq'
plot_phyloseq(physeq, ...)

Arguments

physeq

(Required). phyloseq-class. The actual plot type depends on the available (non-empty) component data types contained within.

...

(Optional). Additional parameters to be passed on to the respective specific plotting function. See below for different plotting functions that might be called by this generic plotting wrapper.

Value

A plot is created. The nature and class of the plot depends on the physeq argument, specifically, which component data classes are present.

See Also

phyloseq frontpage tutorials.

plot_ordination plot_heatmap plot_tree plot_network plot_bar plot_richness

Examples

data(esophagus)
plot_phyloseq(esophagus)

Plot alpha diversity, flexibly with ggplot2

Description

There are many useful examples of alpha-diversity graphics in the phyloseq online tutorials. This function estimates a number of alpha-diversity metrics using the estimate_richness function, and returns a ggplot plotting object. The plot generated by this function will include every sample in physeq, but they can be further grouped on the horizontal axis through the argument to x, and shaded according to the argument to color (see below). You must use untrimmed, non-normalized count data for meaningful results, as many of these estimates are highly dependent on the number of singletons. You can always trim the data later on if needed, just not before using this function.

Usage

plot_richness(physeq, x = "samples", color = NULL, shape = NULL,
  title = NULL, scales = "free_y", nrow = 1, shsi = NULL,
  measures = NULL, sortby = NULL)

Arguments

physeq

(Required). phyloseq-class, or alternatively, an otu_table-class. The data about which you want to estimate.

x

(Optional). A variable to map to the horizontal axis. The vertical axis will be mapped to the alpha diversity index/estimate and have units of total taxa, and/or index value (dimensionless). This parameter (x) can be either a character string indicating a variable in sample_data (among the set returned by sample_variables(physeq) ); or a custom supplied vector with length equal to the number of samples in the dataset (nsamples(physeq)).

The default value is "samples", which will map each sample's name to a separate horizontal position in the plot.

color

(Optional). Default NULL. The sample variable to map to different colors. Like x, this can be a single character string of the variable name in sample_data (among the set returned by sample_variables(physeq) ); or a custom supplied vector with length equal to the number of samples in the dataset (nsamples(physeq)). The color scheme is chosen automatically by link{ggplot}, but it can be modified afterward with an additional layer using scale_color_manual.

shape

(Optional). Default NULL. The sample variable to map to different shapes. Like x and color, this can be a single character string of the variable name in sample_data (among the set returned by sample_variables(physeq) ); or a custom supplied vector with length equal to the number of samples in the dataset (nsamples(physeq)). The shape scale is chosen automatically by link{ggplot}, but it can be modified afterward with an additional layer using scale_shape_manual.

title

(Optional). Default NULL. Character string. The main title for the graphic.

scales

(Optional). Default "free_y". Whether to let vertical axis have free scale that adjusts to the data in each panel. This argument is passed to facet_wrap. If set to "fixed", a single vertical scale will be used in all panels. This can obscure values if the measures argument includes both richness estimates and diversity indices, for example.

nrow

(Optional). Default is 1, meaning that all plot panels will be placed in a single row, side-by-side. This argument is passed to facet_wrap. If NULL, the number of rows and columns will be chosen automatically (wrapped) based on the number of panels and the size of the graphics device.

shsi

(Deprecated). No longer supported. Instead see 'measures' below.

measures

(Optional). Default is NULL, meaning that all available alpha-diversity measures will be included in plot panels. Alternatively, you can specify one or more measures as a character vector of measure names. Values must be among those supported: c("Observed", "Chao1", "ACE", "Shannon", "Simpson", "InvSimpson", "Fisher").

sortby

(Optional). A character string subset of measures argument. Sort x-indices by the mean of one or more measures, if x-axis is mapped to a discrete variable. Default is NULL, implying that a discrete-value horizontal axis will use default sorting, usually alphabetic.

Details

NOTE: Because this plotting function incorporates the output from estimate_richness, the variable names of that output should not be used as x or color (even if it works, the resulting plot might be kindof strange, and not the intended behavior of this function). The following are the names you will want to avoid using in x or color:

c("Observed", "Chao1", "ACE", "Shannon", "Simpson", "InvSimpson", "Fisher").

Value

A ggplot plot object summarizing the richness estimates, and their standard error.

See Also

estimate_richness

estimateR

diversity

There are many more interesting examples at the phyloseq online tutorials.

Examples

## There are many more interesting examples at the phyloseq online tutorials.
## http://joey711.github.io/phyloseq/plot_richness-examples
data("soilrep")
plot_richness(soilrep, measures=c("InvSimpson", "Fisher"))
plot_richness(soilrep, "Treatment", "warmed", measures=c("Chao1", "ACE", "InvSimpson"), nrow=3)
data("GlobalPatterns")
plot_richness(GlobalPatterns, x="SampleType", measures=c("InvSimpson"))
plot_richness(GlobalPatterns, x="SampleType", measures=c("Chao1", "ACE", "InvSimpson"), nrow=3)
plot_richness(GlobalPatterns, x="SampleType", measures=c("Chao1", "ACE", "InvSimpson"), nrow=3, sortby = "Chao1")

General ordination eigenvalue plotter using ggplot2.

Description

Convenience wrapper for plotting ordination eigenvalues (if available) using a ggplot2-graphic.

Usage

plot_scree(ordination, title = NULL)

Arguments

ordination

(Required). An ordination object. Many different classes of ordination are defined by R packages. Ordination classes currently supported/created by the ordinate function are supported here. There is no default, as the expectation is that the ordination will be performed and saved prior to calling this plot function.

title

(Optional). Default NULL. Character string. The main title for the graphic.

Value

A ggplot plot object, graphically summarizing the ordination result for the specified axes.

See Also

plot_ordination

ordinate

distance

phyloseq online tutorials

Examples

# First load and trim a dataset
data("GlobalPatterns")
GP = prune_taxa(names(sort(taxa_sums(GlobalPatterns), TRUE)[1:50]), GlobalPatterns)
# Test plots (preforms ordination in-line, then makes scree plot)
plot_scree(ordinate(GP, "DPCoA", "bray"))
plot_scree(ordinate(GP, "PCoA", "bray"))
# Empty return with message
plot_scree(ordinate(GP, "NMDS", "bray"))
# Constrained ordinations
plot_scree(ordinate(GP, "CCA", formula=~SampleType))
plot_scree(ordinate(GP, "RDA", formula=~SampleType)) 
plot_scree(ordinate(GP, "CAP", formula=~SampleType)) 
# Deprecated example of constrained ordination (emits a warning)
#plot_scree(ordinate(GP ~ SampleType, "RDA")) 
plot_scree(ordinate(GP, "DCA"))
plot_ordination(GP, ordinate(GP, "DCA"), type="scree")

Plot a phylogenetic tree with optional annotations

Description

There are many useful examples of phyloseq tree graphics in the phyloseq online tutorials. This function is intended to facilitate easy graphical investigation of the phylogenetic tree, as well as sample data. Note that for phylogenetic sequencing of samples with large richness, some of the options in this function will be prohibitively slow to render, or too dense to be interpretable. A rough “rule of thumb” is to use subsets of data with not many more than 200 OTUs per plot, sometimes less depending on the complexity of the additional annotations being mapped to the tree. It is usually possible to create an unreadable, uninterpretable tree with modern datasets. However, the goal should be toward parameter settings and data subsets that convey (honestly, accurately) some biologically relevant feature of the data. One of the goals of the phyloseq-package is to make the determination of these features/settings as easy as possible.

Usage

plot_tree(physeq, method = "sampledodge", nodelabf = NULL,
  color = NULL, shape = NULL, size = NULL, min.abundance = Inf,
  label.tips = NULL, text.size = NULL, sizebase = 5,
  base.spacing = 0.02, ladderize = FALSE, plot.margin = 0.2,
  title = NULL, treetheme = NULL, justify = "jagged")

Arguments

physeq

(Required). The data about which you want to plot and annotate a phylogenetic tree, in the form of a single instance of the phyloseq-class, containing at minimum a phylogenetic tree component (try phy_tree). One of the major advantages of this function over basic tree-plotting utilities in the ape-package is the ability to easily annotate the tree with sample variables and taxonomic information. For these uses, the physeq argument should also have a sample_data and/or tax_table component(s).

method

(Optional). Character string. Default "sampledodge". The name of the annotation method to use. This will be expanded in future versions. Currently only "sampledodge" and "treeonly" are supported. The "sampledodge" option results in points drawn next to leaves if individuals from that taxa were observed, and a separate point is drawn for each sample.

nodelabf

(Optional). A function. Default NULL. If NULL, the default, a function will be selected for you based upon whether or not there are node labels in phy_tree(physeq). For convenience, the phyloseq package includes two generator functions for adding arbitrary node labels (can be any character string), nodeplotdefault; as well as for adding bootstrap values in a certain range, nodeplotboot. To not have any node labels in the graphic, set this argument to nodeplotblank.

color

(Optional). Character string. Default NULL. The name of the variable in physeq to map to point color. Supported options here also include the reserved special variables of psmelt.

shape

(Optional). Character string. Default NULL. The name of the variable in physeq to map to point shape. Supported options here also include the reserved special variables of psmelt.

size

(Optional). Character string. Default NULL. The name of the variable in physeq to map to point size. A special argument "abundance" is reserved here and scales point size using abundance in each sample on a log scale. Supported options here also include the reserved special variables of psmelt.

min.abundance

(Optional). Numeric. The minimum number of individuals required to label a point with the precise number. Default is Inf, meaning that no points will have their abundance labeled. If a vector, only the first element is used.

label.tips

(Optional). Character string. Default is NULL, indicating that no tip labels will be printed. If "taxa_names", then the name of the taxa will be added to the tree; either next to the leaves, or next to the set of points that label the leaves. Alternatively, if this is one of the rank names (from rank_names(physeq)), then the identity (if any) for that particular taxonomic rank is printed instead.

text.size

(Optional). Numeric. Should be positive. The size parameter used to control the text size of taxa labels. Default is NULL. If left NULL, this function will automatically calculate a (hopefully) optimal text size given the vertical constraints posed by the tree itself. This argument is included in case the automatically-calculated size is wrong, and you want to change it. Note that this parameter is only meaningful if label.tips is not NULL.

sizebase

(Optional). Numeric. Should be positive. The base of the logarithm used to scale point sizes to graphically represent abundance of species in a given sample. Default is 5.

base.spacing

(Optional). Numeric. Default is 0.02. Should be positive. This defines the base-spacing between points at each tip/leaf in the the tree. The larger this value, the larger the spacing between points. This is useful if you have problems with overlapping large points and/or text indicating abundance, for example. Similarly, if you don't have this problem and want tighter point-spacing, you can shrink this value.

ladderize

(Optional). Boolean or character string (either FALSE, TRUE, or "left"). Default is FALSE. This parameter specifies whether or not to ladderize the tree (i.e., reorder nodes according to the depth of their enclosed subtrees) prior to plotting. This tends to make trees more aesthetically pleasing and legible in a graphical display. When TRUE or "right", “right” ladderization is used. When set to FALSE, no ladderization is applied. When set to "left", the reverse direction (“left” ladderization) is applied. This argument is passed on to tree_layout.

plot.margin

(Optional). Numeric. Default is 0.2. Should be positive. This defines how much right-hand padding to add to the tree plot, which can be required to not truncate tip labels. The margin value is specified as a fraction of the overall tree width which is added to the right side of the plot area. So a value of 0.2 adds twenty percent extra space to the right-hand side of the plot.

title

(Optional). Default NULL. Character string. The main title for the graphic.

treetheme

(Optional). A custom ggplot2 theme layer to use for the tree. Supplants any default theme layers used within the function. A value of NULL uses a default, minimal-annotations theme. If anything other than a them or NULL, the current global ggplot2 theme will result.

justify

(Optional). A character string indicating the type of justification to use on dodged points and tip labels. A value of "jagged", the default, results in these tip-mapped elements being spaced as close to the tips as possible without gaps. Currently, any other value for justify results in a left-justified arrangement of both labels and points.

Details

This function received an early development contribution from the work of Gregory Jordan via the ggphylo package. plot_tree has since been re-written. For details see tree_layout.

Value

A ggplot2 plot.

See Also

plot.phylo

There are many useful examples of phyloseq tree graphics in the phyloseq online tutorials.

Examples

# # Using plot_tree() with the esophagus dataset.
# # Please note that many more interesting examples are shown
# # in the online tutorials"
# # http://joey711.github.io/phyloseq/plot_tree-examples
data(esophagus)
# plot_tree(esophagus)
# plot_tree(esophagus, color="Sample")
# plot_tree(esophagus, size="Abundance")
# plot_tree(esophagus, size="Abundance", color="samples")
plot_tree(esophagus, size="Abundance", color="Sample", base.spacing=0.03)
plot_tree(esophagus, size="abundance", color="samples", base.spacing=0.03)

Define a subset of samples to keep in a phyloseq object.

Description

An S4 Generic method for pruning/filtering unwanted samples by defining those you want to keep.

Usage

prune_samples(samples, x)

## S4 method for signature 'character,otu_table'
prune_samples(samples, x)

## S4 method for signature 'character,sample_data'
prune_samples(samples, x)

## S4 method for signature 'character,phyloseq'
prune_samples(samples, x)

## S4 method for signature 'logical,ANY'
prune_samples(samples, x)

Arguments

samples

(Required). A character vector of the samples in object x that you want to keep – OR alternatively – a logical vector where the kept samples are TRUE, and length is equal to the number of samples in object x. If samples is a named logical, the samples retained is based on those names. Make sure they are compatible with the sample_names of the object you are modifying (x).

x

A phyloseq object.

Value

The class of the object returned by prune_samples matches the class of the phyloseq object, x.

See Also

subset_samples

Examples

data(GlobalPatterns)
 # Subset to just the Chlamydiae phylum.
 GP.chl <- subset_taxa(GlobalPatterns, Phylum=="Chlamydiae")
 # Remove the samples that have less than 20 total reads from Chlamydiae
 GP.chl <- prune_samples(sample_sums(GP.chl)>=20, GP.chl)
 # (p <- plot_tree(GP.chl, color="SampleType", shape="Family", label.tips="Genus", size="abundance"))

Prune unwanted OTUs / taxa from a phylogenetic object.

Description

An S4 Generic method for removing (pruning) unwanted OTUs/taxa from phylogenetic objects, including phylo-class trees, as well as native phyloseq package objects. This is particularly useful for pruning a phyloseq object that has more than one component that describes OTUs. Credit: the phylo-class version is adapted from prune.sample.

Usage

prune_taxa(taxa, x)

## S4 method for signature ''NULL',ANY'
prune_taxa(taxa, x)

## S4 method for signature 'logical,ANY'
prune_taxa(taxa, x)

## S4 method for signature 'character,phylo'
prune_taxa(taxa, x)

## S4 method for signature 'character,otu_table'
prune_taxa(taxa, x)

## S4 method for signature 'character,sample_data'
prune_taxa(taxa, x)

## S4 method for signature 'character,phyloseq'
prune_taxa(taxa, x)

## S4 method for signature 'character,taxonomyTable'
prune_taxa(taxa, x)

## S4 method for signature 'character,XStringSet'
prune_taxa(taxa, x)

Arguments

taxa

(Required). A character vector of the taxa in object x that you want to keep – OR alternatively – a logical vector where the kept taxa are TRUE, and length is equal to the number of taxa in object x. If taxa is a named logical, the taxa retained are based on those names. Make sure they are compatible with the taxa_names of the object you are modifying (x).

x

(Required). A phylogenetic object, including phylo trees, as well as all phyloseq classes that represent taxa. If the function taxa_names returns a non-NULL value, then your object can be pruned by this function.

Value

The class of the object returned by prune_taxa matches the class of the argument, x.

See Also

prune_samples

prune.sample

Examples

data("esophagus")
esophagus
plot(sort(taxa_sums(esophagus), TRUE), type="h", ylim=c(0, 50))
x1 = prune_taxa(taxa_sums(esophagus) > 10, esophagus) 
x2 = prune_taxa(names(sort(taxa_sums(esophagus), TRUE))[1:9], esophagus) 
identical(x1, x2)

Melt phyloseq data object into large data.frame

Description

The psmelt function is a specialized melt function for melting phyloseq objects (instances of the phyloseq class), usually for producing graphics with ggplot2. psmelt relies heavily on the melt and merge functions. The naming conventions used in downstream phyloseq graphics functions have reserved the following variable names that should not be used as the names of sample_variables or taxonomic rank_names. These reserved names are c("Sample", "Abundance", "OTU"). Also, you should not have identical names for sample variables and taxonomic ranks. That is, the intersection of the output of the following two functions sample_variables, rank_names should be an empty vector (e.g. intersect(sample_variables(physeq), rank_names(physeq))). All of these potential name collisions are checked-for and renamed automtically with a warning. However, if you (re)name your variables accordingly ahead of time, it will reduce confusion and eliminate the warnings.

Usage

psmelt(physeq)

Arguments

physeq

(Required). An otu_table-class or phyloseq-class. Function most useful for phyloseq-class.

Details

Note that “melted” phyloseq data is stored much less efficiently, and so RAM storage issues could arise with a smaller dataset (smaller number of samples/OTUs/variables) than one might otherwise expect. For common sizes of graphics-ready datasets, however, this should not be a problem. Because the number of OTU entries has a large effect on the RAM requirement, methods to reduce the number of separate OTU entries – for instance by agglomerating OTUs based on phylogenetic distance using tip_glom – can help alleviate RAM usage problems. This function is made user-accessible for flexibility, but is also used extensively by plot functions in phyloseq.

Value

A data.frame-class table.

See Also

plot_bar

melt

merge

Examples

data("GlobalPatterns")
gp.ch = subset_taxa(GlobalPatterns, Phylum == "Chlamydiae")
mdf = psmelt(gp.ch)
nrow(mdf)
ncol(mdf)
colnames(mdf)
head(rownames(mdf))
# Create a ggplot similar to
library("ggplot2")
p = ggplot(mdf, aes(x=SampleType, y=Abundance, fill=Genus))
p = p + geom_bar(color="black", stat="identity", position="stack")
print(p)

Retrieve the names of the taxonomic ranks

Description

This is a simple accessor function to make it more convenient to determine the taxonomic ranks that are available in a given phyloseq-class object.

Usage

rank_names(physeq, errorIfNULL=TRUE)

Arguments

physeq

(Required). taxonomyTable-class, or phyloseq-class.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE.

Value

Character vector. The names of the available taxonomic ranks.

See Also

get_taxa taxa_names sample_names

Examples

data(enterotype)
rank_names(enterotype)

Resample an OTU table such that all samples have the same library size.

Description

Please note that the authors of phyloseq do not advocate using this as a normalization procedure, despite its recent popularity. Our justifications for using alternative approaches to address disparities in library sizes have been made available as an article in PLoS Computational Biology. See phyloseq_to_deseq2 for a recommended alternative to rarefying directly supported in the phyloseq package, as well as the supplemental materials for the PLoS-CB article and the phyloseq extensions repository on GitHub. Nevertheless, for comparison and demonstration, the rarefying procedure is implemented here in good faith and with options we hope are useful. This function uses the standard R sample function to resample from the abundance values in the otu_table component of the first argument, physeq. Often one of the major goals of this procedure is to achieve parity in total number of counts between samples, as an alternative to other formal normalization procedures, which is why a single value for the sample.size is expected. This kind of resampling can be performed with and without replacement, with replacement being the more computationally-efficient, default setting. See the replace parameter documentation for more details. We recommended that you explicitly select a random number generator seed before invoking this function, or, alternatively, that you explicitly provide a single positive integer argument as rngseed.

Usage

rarefy_even_depth(physeq, sample.size = min(sample_sums(physeq)),
  rngseed = FALSE, replace = TRUE, trimOTUs = TRUE, verbose = TRUE)

Arguments

physeq

(Required). A phyloseq-class object that you want to trim/filter.

sample.size

(Optional). A single integer value equal to the number of reads being simulated, also known as the depth, and also equal to each value returned by sample_sums on the output.

rngseed

(Optional). A single integer value passed to set.seed, which is used to fix a seed for reproducibly random number generation (in this case, reproducibly random subsampling). The default value is 711. If set to FALSE, then no fiddling with the RNG seed is performed, and it is up to the user to appropriately call set.seed beforehand to achieve reproducible results.

replace

(Optional). Logical. Whether to sample with replacement (TRUE) or without replacement (FALSE). The default is with replacement (replace=TRUE). Two implications to consider are that (1) sampling with replacement is faster and more memory efficient as currently implemented; and (2), sampling with replacement means that there is a chance that the number of reads for a given OTU in a given sample could be larger than the original count value, as opposed to sampling without replacement where the original count value is the maximum possible. Prior to phyloseq package version number 1.5.20, this parameter did not exist and sampling with replacement was the only random subsampling implemented in the rarefy_even_depth function. Note that this default behavior was selected for computational efficiency, but differs from analogous functions in related packages (e.g. subsampling in QIIME).

trimOTUs

(Optional). logical(1). Whether to trim OTUs from the dataset that are no longer observed in any sample (have a count of zero in every sample). The number of OTUs trimmed, if any, is printed to standard out as a reminder.

verbose

(Optional). Logical. Default is TRUE. If TRUE, extra non-warning, non-error messages are printed to standard out, describing steps in the rarefying process, the OTUs and samples removed, etc. This can be useful the first few times the function is executed, but can be set to FALSE as-needed once behavior has been verified as expected.

Details

This approach is sometimes mistakenly called “rarefaction”, which in physics refers to a form of wave decompression; but in this context, ecology, the term refers to a repeated sampling procedure to assess species richness, first proposed in 1968 by Howard Sanders. In contrast, the procedure implemented here is used as an ad hoc means to normalize microbiome counts that have resulted from libraries of widely-differing sizes. Here we have intentionally adopted an alternative name, rarefy, that has also been used recently to describe this process and, to our knowledge, not previously used in ecology.

Make sure to use set.seed for exactly-reproducible results of the random subsampling.

Value

An object of class phyloseq. Only the otu_table component is modified.

See Also

sample

set.seed

Examples

# Test with esophagus dataset
data("esophagus")
esorepT = rarefy_even_depth(esophagus, replace=TRUE)
esorepF = rarefy_even_depth(esophagus, replace=FALSE)
sample_sums(esophagus)
sample_sums(esorepT)
sample_sums(esorepF)
## NRun Manually: Too slow!
# data("GlobalPatterns")
# GPrepT = rarefy_even_depth(GlobalPatterns, 1E5, replace=TRUE)
## Actually just this one is slow
# system.time(GPrepF <- rarefy_even_depth(GlobalPatterns, 1E5, replace=FALSE))

Somewhat flexible tree-import function

Description

This function is a convenience wrapper around the read.tree (Newick-format) and read.nexus (Nexus-format) importers provided by the ape-package. This function attempts to return a valid tree if possible using either format importer. If it fails, it silently returns NULL by default, rather than throwing a show-stopping error.

Usage

read_tree(treefile, errorIfNULL=FALSE, ...)

Arguments

treefile

(Required). A character string implying a file connection (like a path or URL), or an actual connection. Must be a Newick- or Nexus-formatted tree.

errorIfNULL

(Optional). Logical. Should an error be thrown if no tree can be extracted from the connection? Default is FALSE, indicating that NULL will be SILENTLY returned, rather than an error. Be cautious about this behavior. Useful for phyloseq internals, but might be hard to track in your own code if you're not aware of this “no error by default” setting. If this is a problem, change this value to TRUE, and you can still use the function.

...

(Optional). Additional parameter(s) passed to the relevant tree-importing function.

Value

If successful, returns a phylo-class object as defined in the ape-package. Returns NULL if neither tree-reading function worked.

See Also

read_tree_greengenes

phylo

read.tree

read.nexus

Examples

read_tree(system.file("extdata", "esophagus.tree.gz", package="phyloseq"))
read_tree(system.file("extdata", "GP_tree_rand_short.newick.gz", package="phyloseq"))

Read GreenGenes tree released in annotated newick format

Description

In principal, this is a standard newick format, that can be imported into R using read_tree, which in-turn utilizes read.tree. However, read.tree has failed to import recent (October 2012 and later) releases of the GreenGenes tree, and this problem has been traced to the additional annotations added to some internal nodes that specify taxonomic classification between single-quotes. To solve this problem and create a clear container for fixing future problems with the format of GreenGenes-released trees, this function is available in phyloseq and exported for users. It is also referenced in the documentation of the import functions for QIIME legacy and BIOM format importers – import_qiime and import_biom, respectively. However, since the precise format of the tree is not restricted to GreenGenes trees by QIIME or for the biom-format, this function is not called automatically by those aforementioned import functions. If your tree is formatted like, or is one of, the official GreenGenes release trees, then you should use this function and provide its output to your relevant import function.

Usage

read_tree_greengenes(treefile)

Arguments

treefile

(Required). A character string implying a file connection (like a path or URL), or an actual connection. Must be a Newick–formatted tree released by GreenGenes in October 2012 or later. The similarity threshold of the OTUs should not matter, except that it should match your OTU table.

Value

A tree, represented as a phylo object.

Examples

# Read the May 2013, 73% similarity official tree,
# included as extra data in phyloseq.
treefile = system.file("extdata", "gg13-5-73.tree.gz", package="phyloseq")
x = read_tree_greengenes(treefile)
x
class(x)
y = read_tree(treefile)
y
class(y)
## Not run, causes an error:
# library("ape")
# read.tree(treefile)

Retrieve reference sequences (XStringSet-class) from object.

Description

This is the suggested method for accessing the phylogenetic tree, (XStringSet-class) from a phyloseq data object (phyloseq-class). Like other accessors (see See Also, below), the default behavior of this method is to stop with an error if physeq is a phyloseq-class but does not contain reference sequences (the component data type you are trying to access in this case).

Usage

refseq(physeq, errorIfNULL=TRUE)

## S4 method for signature 'ANY'
refseq(physeq, errorIfNULL = TRUE)

## S4 method for signature 'XStringSet'
refseq(physeq)

Arguments

physeq

(Required). An instance of phyloseq-class that contains a phylogenetic tree. If physeq is a phylogenetic tree (a component data class), then it is returned as-is.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE.

Value

The phylo-class object contained within physeq; or NULL if physeq does not have a tree. This method stops with an error in the latter NULL case be default, which can be over-ridden by changing the value of errorIfNULL to FALSE.

See Also

otu_table, sample_data, tax_table phy_tree, phyloseq, merge_phyloseq

Examples

data(GlobalPatterns)
 refseq(GlobalPatterns, FALSE)

Set to FALSE any outlier species greater than f fractional abundance.

Description

This is for removing overly-abundant outlier taxa, not for trimming low-abundance taxa.

Usage

rm_outlierf(f, na.rm=TRUE)

Arguments

f

Single numeric value between 0 and 1. The maximum fractional abundance value that a taxa will be allowed to have in a sample without being marked for trimming.

na.rm

Logical. Should we remove NA values. Default TRUE.

Value

A function (enclosure), suitable for filterfun_sample.

See Also

topk, topf, topp, rm_outlierf

Examples

t1 <- 1:10; names(t1)<-paste("t", 1:10, sep="")
rm_outlierf(0.15)(t1)
## Use simulated abundance matrix
set.seed(711)
testOTU <- otu_table(matrix(sample(1:50, 25, replace=TRUE), 5, 5), taxa_are_rows=FALSE)
taxa_sums(testOTU)
f1  <- filterfun_sample(rm_outlierf(0.1))
(wh1 <- genefilter_sample(testOTU, f1, A=1))
wh2 <- c(TRUE, TRUE, TRUE, FALSE, FALSE)
prune_taxa(wh1, testOTU)
prune_taxa(wh2, testOTU)

Build or access sample_data.

Description

This is the suggested method for both constructing and accessing a table of sample-level variables (sample_data-class), which in the phyloseq-package is represented as a special extension of the data.frame-class. When the argument is a data.frame, sample_data will create a sample_data-class object. In this case, the rows should be named to match the sample_names of the other objects to which it will ultimately be paired. Alternatively, if the first argument is an experiment-level (phyloseq-class) object, then the corresponding sample_data is returned. Like other accessors (see See Also, below), the default behavior of this method is to stop with an error if object is a phyloseq-class but does not contain a sample_data.

Usage

sample_data(object, errorIfNULL=TRUE)

## S4 method for signature 'ANY'
sample_data(object, errorIfNULL = TRUE)

## S4 method for signature 'data.frame'
sample_data(object)

Arguments

object

(Required). A data.frame-class, or a phyloseq-class object.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE.

Value

A sample_data-class object representing the sample variates of an experiment.

See Also

phy_tree, tax_table, otu_table phyloseq, merge_phyloseq

Examples

#
data(soilrep)
head(sample_data(soilrep))

The S4 for storing sample variables.

Description

Row indices represent samples, while column indices represent experimental categories, variables (and so forth) that describe the samples.

Details

.Data

data-frame data, inherited from the data.frame class.

row.names

Also inherited from the data.frame class; it should contain the sample names.

names

Inherited from the data.frame class.


Assign (new) sample_data to x

Description

This replaces the current sample_data component of x with value, if value is a sample_data-class. However, if value is a data.frame, then value is first coerced to a sample_data-class, and then assigned. Alternatively, if value is phyloseq-class, then the sample_data component will first be accessed from value and then assigned. This makes possible some concise assignment/replacement statements when adjusting, modifying, or building subsets of experiment-level data. See some examples below.

Internally, this re-builds the phyloseq-class object using the standard phyloseq constructor. Thus, index mismatches between sample-describing components will not be allowed, and subsetting will occurr automatically such that only the intersection of sample IDs are included in any components. This has the added benefit of re-checking (internally) for any other issues.

Usage

sample_data(x) <- value

Arguments

x

(Required). phyloseq-class. The object to modify.

value

(Required). Either a sample_data-class, a data.frame that can be coerced into sample_data-class, or a phyloseq-class that contains a suitable sample_data component to assign to x. If unsure, try sample_data(value), which should return a sample_data-class object without error.

Value

No return. This is an assignment statement.

Examples

data(soilrep)
 soilrep
 head(sample_data(soilrep))
 sample_data(soilrep)$Time <- as.integer(substr(sample_data(soilrep)$Sample, 1, 1))
 head(sample_data(soilrep))

Get sample names.

Description

Get sample names.

Usage

sample_names(physeq)

## S4 method for signature 'ANY'
sample_names(physeq)

## S4 method for signature 'phyloseq'
sample_names(physeq)

## S4 method for signature 'sample_data'
sample_names(physeq)

## S4 method for signature 'otu_table'
sample_names(physeq)

Arguments

physeq

(Required). A phyloseq-class, sample_data, or otu_table-class.

Value

A character vector. The names of the samples in physeq.

See Also

taxa_names, nsamples

Examples

data(esophagus)
sample_names(esophagus)

Replace OTU identifier names

Description

Replace OTU identifier names

Usage

sample_names(x) <- value

## S4 replacement method for signature 'ANY,ANY'
sample_names(x) <- value

## S4 replacement method for signature 'ANY,character'
sample_names(x) <- value

## S4 replacement method for signature 'otu_table,character'
sample_names(x) <- value

## S4 replacement method for signature 'sample_data,character'
sample_names(x) <- value

## S4 replacement method for signature 'phyloseq,character'
sample_names(x) <- value

Arguments

x

(Required). An object defined by the phyloseq-package that describes OTUs in some way.

value

(Required). A character vector to replace the current sample_names.

Examples

data("esophagus")
sample_names(esophagus)
# plot_tree(esophagus, color="sample_names", ladderize="left")
sample_names(esophagus) <- paste("Sa-", sample_names(esophagus), sep="")
sample_names(esophagus)
# plot_tree(esophagus, color="sample_names", ladderize="left") 
## non-characters are first coerced to characters.
sample_names(esophagus) <- 1:nsamples(esophagus)
sample_names(esophagus)
# plot_tree(esophagus, color="sample_names", ladderize="left") 
## Cannot assign non-unique or differently-lengthed name vectors. Error.
# sample_names(esophagus) <- sample(c(TRUE, FALSE), nsamples(esophagus), TRUE)
# sample_names(esophagus) <- sample(sample_names(esophagus), nsamples(esophagus)-1, FALSE)

Returns the total number of individuals observed from each sample.

Description

A convenience function equivalent to rowSums or colSums, but where the orientation of the otu_table is automatically handled.

Usage

sample_sums(x)

Arguments

x

otu_table-class, or phyloseq-class.

Value

A named numeric-class length equal to the number of samples in the x, name indicating the sample ID, and value equal to the sum of all individuals observed for each sample in x.

See Also

taxa_sums, rowSums, colSums

Examples

data(enterotype)
sample_sums(enterotype)
data(esophagus)
sample_sums(esophagus)

Get the sample variables present in sample_data

Description

This is a simple accessor function to make it more convenient to determine the sample variable names of a particular phyloseq-class object.

Usage

sample_variables(physeq, errorIfNULL=TRUE)

Arguments

physeq

(Required). sample_data-class, or phyloseq-class.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE.

Value

Character vector. The names of the variables in the sample_data data.frame. Essentially the column names. Useful for selecting model and graphics parameters that interact with sample_data.

See Also

get_taxa taxa_names sample_names

Examples

data(enterotype)
sample_variables(enterotype)

Show cutoff values available in a mothur file.

Description

This is a helper function to report back to the user the different cutoff values available in a given mothur file – for instance, a list or shared file.

Usage

show_mothur_cutoffs(mothur_list_file)

Arguments

mothur_list_file

The file name and/or location as produced by mothur.

Value

A character vector of the different cutoff values contained in the file. For a given set of arguments to the cluster() command from within mothur, a number of OTU-clustering results are returned in the same file. The exact cutoff values used by mothur can vary depending on the input data/parameters. This simple function returns the cutoffs that were actually included in the mothur output. This an important extra step prior to importing data with the import_mothur function.

See Also

import_mothur


method extensions to show for phyloseq objects.

Description

See the general documentation of show method for expected behavior.

Usage

## S4 method for signature 'otu_table'
show(object)

## S4 method for signature 'sample_data'
show(object)

## S4 method for signature 'taxonomyTable'
show(object)

## S4 method for signature 'phyloseq'
show(object)

Arguments

object

Any R object

See Also

show

Examples

# data(GlobalPatterns)
# show(GlobalPatterns)
# GlobalPatterns

Subset points from an ordination-derived ggplot

Description

Easily retrieve a plot-derived data.frame with a subset of points according to a threshold and method. The meaning of the threshold depends upon the method. See argument description below. There are many useful examples of phyloseq ordination graphics in the phyloseq online tutorials.

Usage

subset_ord_plot(p, threshold=0.05, method="farthest")

Arguments

p

(Required). A ggplot object created by plot_ordination. It contains the complete data that you want to subset.

threshold

(Optional). A numeric scalar. Default is 0.05. This value determines a coordinate threshold or population threshold, depending on the value of the method argument, ultimately determining which points are included in returned data.frame.

method

(Optional). A character string. One of c("farthest", "radial", "square"). Default is "farthest". This determines how threshold will be interpreted.

farthest

Unlike the other two options, this option implies removing a certain fraction or number of points from the plot, depending on the value of threshold. If threshold is greater than or equal to 1, then all but threshold number of points farthest from the origin are removed. Otherwise, if threshold is less than 1, all but threshold fraction of points farthests from origin are retained.

radial

Keep only those points that are beyond threshold radial distance from the origin. Has the effect of removing a circle of points from the plot, centered at the origin.

square

Keep only those points with at least one coordinate greater than threshold. Has the effect of removing a “square” of points from the plot, centered at the origin.

Value

A data.frame suitable for creating a ggplot plot object, graphically summarizing the ordination result according to previously-specified parameters.

See Also

phyloseq online tutorial for this function.

plot_ordination

Examples

## See the online tutorials.
## http://joey711.github.io/phyloseq/subset_ord_plot-examples

Subset samples by sample_data expression

Description

This is a convenience wrapper around the subset function. It is intended to allow subsetting complex experimental objects with one function call. Subsetting is based on an expression for which the context first includes the variables contained in sample_data. The samples retained in the dataset is equivalent to x[subset & !is.na(subset)], where x is the vector of sample IDs and subset is the logical that results from your subsetting expression. This is important to keep in mind, as users are often unaware that this subsetting step also removes/omits samples that have a missing value, NA, somewhere in the expression.

Usage

subset_samples(physeq, ...)

Arguments

physeq

A sample_data-class, or a phyloseq-class object with a sample_data. If the sample_data slot is missing in physeq, then physeq will be returned as-is, and a warning will be printed to screen.

...

The subsetting expression that should be applied to the sample_data. This is passed on to subset, see its documentation for more details.

Value

A subsetted object with the same class as physeq.

See Also

subset_species

Examples

# data(GlobalPatterns)
 # subset_samples(GlobalPatterns, SampleType=="Ocean")

Subset species by taxonomic expression

Description

This is a convenience wrapper around the subset function. It is intended to speed subsetting complex experimental objects with one function call. In the case of subset_taxa, the subsetting will be based on an expression related to the columns and values within the tax_table (taxonomyTable component) slot of physeq. The OTUs retained in the dataset is equivalent to x[subset & !is.na(subset)], where x is the vector of OTU IDs and subset is the logical that results from your subsetting expression. This is important to keep in mind, as users are often unaware that this subsetting step also removes/omits OTUs that have a missing value result, NA, somewhere in the expression.

Usage

subset_taxa(physeq, ...)

Arguments

physeq

A taxonomyTable-class, or phyloseq-class that contains a taxonomyTable. If the tax_table slot is missing in physeq, then physeq will be returned as-is and a warning will be printed to screen.

...

The subsetting expression that should be applied to the taxonomyTable. This is passed on to subset, and more details and examples about how it functions can be found in its documentation.

Value

A subsetted object with the same class as physeq.

See Also

subset_samples

Examples

## ex3 <- subset_taxa(GlobalPatterns, Phylum=="Bacteroidetes")

Transpose otu_table-class or phyloseq-class

Description

Extends the base transpose method, t.

Usage

t(x)

## S4 method for signature 'otu_table'
t(x)

## S4 method for signature 'phyloseq'
t(x)

Arguments

x

An otu_table or phyloseq-class.

Value

The class of the object returned by t matches the class of the argument, x. The otu_table is transposed, and taxa_are_rows value is toggled.

Examples

data(GlobalPatterns)
otu_table(GlobalPatterns)
t( otu_table(GlobalPatterns) )

Agglomerate taxa of the same type.

Description

This method merges species that have the same taxonomy at a certain taxonomic rank. Its approach is analogous to tip_glom, but uses categorical data instead of a tree. In principal, other categorical data known for all taxa could also be used in place of taxonomy, but for the moment, this must be stored in the taxonomyTable of the data. Also, columns/ranks to the right of the rank chosen to use for agglomeration will be replaced with NA, because they should be meaningless following agglomeration.

Usage

tax_glom(physeq, taxrank=rank_names(physeq)[1], NArm=TRUE, bad_empty=c(NA, "", " ", "\t"))

Arguments

physeq

(Required). phyloseq-class or otu_table.

taxrank

A character string specifying the taxonomic level that you want to agglomerate over. Should be among the results of rank_names(physeq). The default value is rank_names(physeq)[1], which may agglomerate too broadly for a given experiment. You are strongly encouraged to try different values for this argument.

NArm

(Optional). Logical, length equal to one. Default is TRUE. CAUTION. The decision to prune (or not) taxa for which you lack categorical data could have a large effect on downstream analysis. You may want to re-compute your analysis under both conditions, or at least think carefully about what the effect might be and the reasons explaining the absence of information for certain taxa. In the case of taxonomy, it is often a result of imprecision in taxonomic designation based on short phylogenetic sequences and a patchy system of nomenclature. If this seems to be an issue for your analysis, think about also trying the nomenclature-agnostic tip_glom method if you have a phylogenetic tree available.

bad_empty

(Optional). Character vector. Default: c(NA, "", " ", "\t"). Defines the bad/empty values that should be ignored and/or considered unknown. They will be removed from the internal agglomeration vector derived from the argument to tax, and therefore agglomeration will not combine taxa according to the presence of these values in tax. Furthermore, the corresponding taxa can be optionally pruned from the output if NArm is set to TRUE.

Value

A taxonomically-agglomerated, optionally-pruned, object with class matching the class of physeq.

See Also

tip_glom

prune_taxa

merge_taxa

Examples

# data(GlobalPatterns)
# ## print the available taxonomic ranks
# colnames(tax_table(GlobalPatterns))
# ## agglomerate at the Family taxonomic rank
# (x1 <- tax_glom(GlobalPatterns, taxrank="Family") )
# ## How many taxa before/after agglomeration?
# ntaxa(GlobalPatterns); ntaxa(x1)
# ## Look at enterotype dataset...
# data(enterotype)
# ## print the available taxonomic ranks. Shows only 1 rank available, not useful for tax_glom
# colnames(tax_table(enterotype))

Build or access the taxonomyTable.

Description

This is the suggested method for both constructing and accessing a table of taxonomic names, organized with ranks as columns (taxonomyTable-class). When the argument is a character matrix, tax_table() will create and return a taxonomyTable-class object. In this case, the rows should be named to match the species.names of the other objects to which it will ultimately be paired. Alternatively, if the first argument is an experiment-level (phyloseq-class) object, then the corresponding taxonomyTable is returned. Like other accessors (see See Also, below), the default behavior of this method is to stop with an error if object is a phyloseq-class but does not contain a taxonomyTable.

Usage

tax_table(object, errorIfNULL=TRUE)

## S4 method for signature 'ANY'
tax_table(object, errorIfNULL = TRUE)

## S4 method for signature 'matrix'
tax_table(object)

## S4 method for signature 'data.frame'
tax_table(object)

Arguments

object

An object among the set of classes defined by the phyloseq package that contain taxonomyTable.

errorIfNULL

(Optional). Logical. Should the accessor stop with an error if the slot is empty (NULL)? Default TRUE.

Value

A taxonomyTable-class object. It is either grabbed from the relevant slot if object is complex, or built anew if object is a character matrix representing the taxonomic classification of species in the experiment.

See Also

phy_tree, sample_data, otu_table phyloseq, merge_phyloseq

Examples

#
# tax1 <- tax_table(matrix("abc", 30, 8))
# data(GlobalPatterns)
# tax_table(GlobalPatterns)

Assign a (new) Taxonomy Table to x

Description

Assign a (new) Taxonomy Table to x

Usage

tax_table(x) <- value

## S4 replacement method for signature 'phyloseq,taxonomyTable'
tax_table(x) <- value

## S4 replacement method for signature 'phyloseq,ANY'
tax_table(x) <- value

## S4 replacement method for signature 'taxonomyTable,taxonomyTable'
tax_table(x) <- value

## S4 replacement method for signature 'taxonomyTable,ANY'
tax_table(x) <- value

Arguments

x

(Required). phyloseq-class

value

(Required). taxonomyTable-class. Alternatively, value can be a phyloseq-class that has a tax_table component, or a matrix-class that can be coerced to a taxonomyTable-class with row indices that match at least some of the taxa_names of x.

Examples

# data(GlobalPatterns)
# # An example of pruning to just the first 100 taxa in GlobalPatterns.
# ex2a <- prune_taxa(taxa_names(GlobalPatterns)[1:100], GlobalPatterns)
# # The following 3 lines produces an ex2b that is equal to ex2a
# ex2b <- GlobalPatterns
# TT <- tax_table(GlobalPatterns)[1:100, ]
# tax_table(ex2b) <- TT
# identical(ex2a, ex2b)
# print(ex2b)
# # 2 examples adding a tax_table component from phyloseq or matrix classes
# ex2c <- phyloseq(otu_table(ex2b), sample_data(ex2b), phy_tree(ex2b))
# tax_table(ex2c) <- ex2b
# identical(ex2a, ex2c)
# ex2c <- phyloseq(otu_table(ex2b), sample_data(ex2b), phy_tree(ex2b))
# tax_table(ex2c) <- as(tax_table(ex2b), "matrix")
# identical(ex2a, ex2c)

Access taxa_are_rows slot from otu_table objects.

Description

Access taxa_are_rows slot from otu_table objects.

Usage

taxa_are_rows(physeq)

## S4 method for signature 'ANY'
taxa_are_rows(physeq)

## S4 method for signature 'otu_table'
taxa_are_rows(physeq)

## S4 method for signature 'phyloseq'
taxa_are_rows(physeq)

Arguments

physeq

(Required). phyloseq-class, or otu_table-class.

Value

A logical indicating the orientation of the otu_table.

See Also

otu_table


Manually change taxa_are_rows through assignment.

Description

The taxa_are_rows slot is a logical indicating the orientation of the abundance table contained in object x.

Usage

taxa_are_rows(x) <- value

## S4 replacement method for signature 'otu_table,logical'
taxa_are_rows(x) <- value

## S4 replacement method for signature 'phyloseq,logical'
taxa_are_rows(x) <- value

Arguments

x

otu_table-class or phyloseq-class

value

A logical of length equal to 1. If length(value) > 1, the additional elements will be ignored. Only the first element is assigned to the taxa_are_rows slot.

Examples

data(esophagus)
 taxa_are_rows(esophagus)
 taxa_are_rows(otu_table(esophagus))

Get species / taxa names.

Description

Get species / taxa names.

Usage

taxa_names(physeq)

## S4 method for signature 'ANY'
taxa_names(physeq)

## S4 method for signature 'phyloseq'
taxa_names(physeq)

## S4 method for signature 'otu_table'
taxa_names(physeq)

## S4 method for signature 'taxonomyTable'
taxa_names(physeq)

## S4 method for signature 'sample_data'
taxa_names(physeq)

## S4 method for signature 'phylo'
taxa_names(physeq)

## S4 method for signature 'XStringSet'
taxa_names(physeq)

Arguments

physeq

phyloseq-class, otu_table-class, taxonomyTable-class, or phylo

Value

A character vector of the names of the species in physeq.

See Also

ntaxa

Examples

#
data("esophagus")
tree <- phy_tree(esophagus)
OTU1 <- otu_table(esophagus)
taxa_names(tree)
taxa_names(OTU1)
physeq1 <- phyloseq(OTU1, tree)
taxa_names(physeq1)

Replace OTU identifier names

Description

Replace OTU identifier names

Usage

taxa_names(x) <- value

## S4 replacement method for signature 'ANY,ANY'
taxa_names(x) <- value

## S4 replacement method for signature 'ANY,character'
taxa_names(x) <- value

## S4 replacement method for signature 'otu_table,character'
taxa_names(x) <- value

## S4 replacement method for signature 'taxonomyTable,character'
taxa_names(x) <- value

## S4 replacement method for signature 'phylo,character'
taxa_names(x) <- value

## S4 replacement method for signature 'XStringSet,character'
taxa_names(x) <- value

## S4 replacement method for signature 'phyloseq,character'
taxa_names(x) <- value

Arguments

x

(Required). An object defined by the phyloseq-package that describes OTUs in some way.

value

(Required). A character vector to replace the current taxa_names.

Examples

data("esophagus")
taxa_names(esophagus)
# plot_tree(esophagus, label.tips="taxa_names", ladderize="left")
taxa_names(esophagus) <- paste("OTU-", taxa_names(esophagus), sep="")
taxa_names(esophagus)
# plot_tree(esophagus, label.tips="taxa_names", ladderize="left")
## non-characters are first coerced to characters.
taxa_names(esophagus) <- 1:ntaxa(esophagus)
taxa_names(esophagus)
# plot_tree(esophagus, label.tips="taxa_names", ladderize="left")
## Cannot assign non-unique or differently-lengthed name vectors. Error.
# taxa_names(esophagus) <- sample(c(TRUE, FALSE), ntaxa(esophagus), TRUE)
# taxa_names(esophagus) <- sample(taxa_names(esophagus), ntaxa(esophagus)-5, FALSE)

Returns the total number of individuals observed from each species/taxa/OTU.

Description

A convenience function equivalent to rowSums or colSums, but where the orientation of the otu_table is automatically handled.

Usage

taxa_sums(x)

Arguments

x

otu_table-class, or phyloseq-class.

Value

A numeric-class with length equal to the number of species in the table, name indicated the taxa ID, and value equal to the sum of all individuals observed for each taxa in x.

See Also

sample_sums, rowSums, colSums

Examples

data(enterotype)
taxa_sums(enterotype)
data(esophagus)
taxa_sums(esophagus)

An S4 class that holds taxonomic classification data as a character matrix.

Description

Row indices represent taxa, columns represent taxonomic classifiers.

Details

.Data

This slot is inherited from the matrix class.


Thresholded rank transformation.

Description

The lowest thresh values in x all get the value 'thresh'.

Usage

threshrank(x, thresh, keep0s=FALSE, ...)

Arguments

x

(Required). Numeric vector to transform.

thresh

A single numeric value giving the threshold.

keep0s

A logical determining whether 0's in x should remain a zero-value in the output. If FALSE, zeros are treated as any other value.

...

Further arguments passes to the rank function.

Value

A ranked, (optionally) thresholded numeric vector with length equal to x. Default arguments to rank are used, unless provided as additional arguments.

See Also

transform_sample_counts, rank, threshrankfun

Examples

#
(a_vector <- sample(0:10, 100, TRUE))
threshrank(a_vector, 5, keep0s=TRUE)
data(GlobalPatterns)
GP <- GlobalPatterns
## These three approaches result in identical otu_table
(x1 <- transform_sample_counts( otu_table(GP), threshrankfun(500)) )
(x2 <- otu_table(apply(otu_table(GP), 2, threshrankfun(500)), taxa_are_rows(GP)) )
identical(x1, x2)
(x3 <- otu_table(apply(otu_table(GP), 2, threshrank, thresh=500), taxa_are_rows(GP)) )
identical(x1, x3)

A closure version of the threshrank function.

Description

Takes the same arguments as threshrank, except for x, because the output is a single-argument function rather than a rank-transformed numeric. This is useful for higher-order functions that require a single-argument function as input, like transform_sample_counts.

Usage

threshrankfun(thresh, keep0s=FALSE, ...)

Arguments

thresh

A single numeric value giving the threshold.

keep0s

A logical determining whether 0's in x should remain a zero-value in the output. If FALSE, zeros are treated as any other value.

...

Further arguments passes to the rank function.

Value

A single-argument function with the options to threshrank set.

See Also

transform_sample_counts, threshrankfun, threshrank

Examples

data(esophagus)
x1 = transform_sample_counts(esophagus, threshrankfun(50))
otu_table(x1)
x2 = transform_sample_counts(esophagus, rank)
otu_table(x2)
identical(x1, x2)

Agglomerate closely-related taxa using single-linkage clustering.

Description

All tips of the tree separated by a cophenetic distance smaller than h will be agglomerated into one taxa using merge_taxa.

Usage

tip_glom(physeq, h = 0.2, hcfun = agnes, ...)

Arguments

physeq

(Required). A phyloseq-class, containing a phylogenetic tree. Alternatively, a phylogenetic tree phylo will also work.

h

(Optional). Numeric scalar of the height where the tree should be cut. This refers to the tree resulting from hierarchical clustering of cophenetic.phylo(phy_tree(physeq)), not necessarily the original phylogenetic tree, phy_tree(physeq). Default value is 0.2. Note that this argument used to be named speciationMinLength, before this function/method was rewritten.

hcfun

(Optional). A function. The (agglomerative, hierarchical) clustering function to use. Good examples are agnes and hclust. The default is agnes.

...

(Optional). Additional named arguments to pass to hcfun.

Details

Can be used to create a non-trivial OTU Table, if a phylogenetic tree is available.

For now, a simple, “greedy”, single-linkage clustering is used. In future releases it should be possible to specify different clustering approaches available in R, in particular, complete-linkage clustering appears to be used more commonly for OTU clustering applications.

Value

An instance of the phyloseq-class. Or alternatively, a phylo object if the physeq argument was just a tree. In the expected-use case, the number of OTUs will be fewer (see ntaxa), after merging OTUs that are related enough to be called the same OTU.

See Also

merge_taxa

agnes

hclust

cophenetic.phylo

phylo

Examples

data("esophagus")
# for speed
esophagus = prune_taxa(taxa_names(esophagus)[1:25], esophagus)
plot_tree(esophagus, label.tips="taxa_names", size="abundance", title="Before tip_glom()")
plot_tree(tip_glom(esophagus, h=0.2), label.tips="taxa_names", size="abundance", title="After tip_glom()")

Make filter fun. that returns the top f fraction of taxa in a sample.

Description

As opposed to topp, which gives the most abundant p fraction of observed taxa (richness, instead of cumulative abundance. Said another way, topf ensures a certain fraction of the total sequences are retained, while topp ensures that a certain fraction of taxa/species/OTUs are retained.

Usage

topf(f, na.rm=TRUE)

Arguments

f

Single numeric value between 0 and 1.

na.rm

Logical. Should we remove NA values. Default TRUE.

Value

A function (enclosure), suitable for filterfun_sample, that will return TRUE for each element in the taxa comprising the most abundant f fraction of individuals.

See Also

topk, topf, topp, rm_outlierf

Examples

t1 <- 1:10; names(t1)<-paste("t", 1:10, sep="")
topf(0.6)(t1)
## Use simulated abundance matrix
set.seed(711)
testOTU <- otu_table(matrix(sample(1:50, 25, replace=TRUE), 5, 5), taxa_are_rows=FALSE)
f1  <- filterfun_sample(topf(0.4))
(wh1 <- genefilter_sample(testOTU, f1, A=1))
wh2 <- c(TRUE, TRUE, TRUE, FALSE, FALSE)
prune_taxa(wh1, testOTU)
prune_taxa(wh2, testOTU)

Make filter fun. the most abundant k taxa

Description

Make filter fun. the most abundant k taxa

Usage

topk(k, na.rm=TRUE)

Arguments

k

An integer, indicating how many of the most abundant taxa should be kept.

na.rm

A logical. Should NAs be removed. Default is TRUE.

Value

Returns a function (enclosure) that will return TRUE for each element in the most abundant k values.

See Also

topk, topf, topp, rm_outlierf

Examples

## Use simulated abundance matrix
set.seed(711)
testOTU <- otu_table(matrix(sample(1:50, 25, replace=TRUE), 5, 5), taxa_are_rows=FALSE)
f1  <- filterfun_sample(topk(2))
wh1 <- genefilter_sample(testOTU, f1, A=2)
wh2 <- c(TRUE, TRUE, TRUE, FALSE, FALSE)
prune_taxa(wh1, testOTU)
prune_taxa(wh2, testOTU)

Make filter fun. that returns the most abundant p fraction of taxa

Description

Make filter fun. that returns the most abundant p fraction of taxa

Usage

topp(p, na.rm=TRUE)

Arguments

p

A numeric of length 1, indicating what fraction of the most abundant taxa should be kept.

na.rm

A logical. Should NAs be removed. Default is TRUE.

Value

A function (enclosure), suitable for filterfun_sample, that will return TRUE for each element in the most abundant p fraction of taxa.

See Also

topk, topf, topp, rm_outlierf

Examples

## Use simulated abundance matrix
set.seed(711)
testOTU <- otu_table(matrix(sample(1:50, 25, replace=TRUE), 5, 5), taxa_are_rows=FALSE)
sample_sums(testOTU)
f1  <- filterfun_sample(topp(0.2))
(wh1 <- genefilter_sample(testOTU, f1, A=1))
wh2 <- c(TRUE, TRUE, TRUE, FALSE, FALSE)
prune_taxa(wh1, testOTU)
prune_taxa(wh2, testOTU)

Transform abundance data in an otu_table, sample-by-sample.

Description

This function transforms the sample counts of a taxa abundance matrix according to a user-provided function. The counts of each sample will be transformed individually. No sample-sample interaction/comparison is possible by this method.

Usage

transform_sample_counts(physeq, fun, ...)

transformSampleCounts(physeq, fun, ...)

Arguments

physeq

(Required). phyloseq-class of otu_table-class.

fun

(Required). A single-argument function that will be applied to the abundance counts of each sample. Can be an anonymous function.

...

(Optional). Additional, optionally-named, arguments passed to fun during transformation of abundance data.

Value

A transformed otu_table – or phyloseq object with its transformed otu_table. In general, trimming is not expected by this method, so it is suggested that the user provide only functions that return a full-length vector. Filtering/trimming can follow, for which the genefilter_sample and prune_taxa functions are suggested.

See Also

threshrankfun, rank, log

Examples

#
data(esophagus)
x1 = transform_sample_counts(esophagus, threshrankfun(50))
head(otu_table(x1), 10)
x2 = transform_sample_counts(esophagus, rank)
head(otu_table(x2), 10)
identical(x1, x2)
x3 = otu_table(esophagus) + 5
x3 = transform_sample_counts(x3, log)
head(otu_table(x3), 10)
x4 = transform_sample_counts(esophagus, function(x) round(x^2.2, 0))
head(otu_table(x4), 10)

Returns a data table defining the line segments of a phylogenetic tree.

Description

This function takes a phylo or phyloseq-class object and returns a list of two data.tables suitable for plotting a phylogenetic tree with ggplot2.

Usage

tree_layout(phy, ladderize = FALSE)

Arguments

phy

(Required). The phylo or phyloseq-class object (which must contain a phylogenetic tree) that you want to converted to data.tables suitable for plotting with ggplot2.

ladderize

(Optional). Boolean or character string (either FALSE, TRUE, or "left"). Default is FALSE (no ladderization). This parameter specifies whether or not to ladderize the tree (i.e., reorder nodes according to the depth of their enclosed subtrees) prior to plotting. This tends to make trees more aesthetically pleasing and legible in a graphical display. When TRUE or "right", “right” ladderization is used. When set to FALSE, no ladderization is applied. When set to "left", the reverse direction (“left” ladderization) is applied.

Value

A list of two data.tables, containing respectively a data.table of edge segment coordinates, named edgeDT, and a data.table of vertical connecting segments, named vertDT. See example below for a simple demonstration.

See Also

An early example of this functionality was borrowed directly, with permission, from the package called ggphylo, released on GitHub at: https://github.com/gjuggler/ggphylo by its author Gregory Jordan [email protected]. That original phyloseq internal function, tree.layout, has been completely replaced by this smaller and much faster user-accessible function that utilizes performance enhancements from standard data.table magic as well as ape-package internal C code.

Examples

library("ggplot2")
data("esophagus")
phy = phy_tree(esophagus)
phy <- ape::root(phy, "65_2_5", resolve.root=TRUE)
treeSegs0 = tree_layout(phy)
treeSegs1 = tree_layout(esophagus)
edgeMap = aes(x=xleft, xend=xright, y=y, yend=y)
vertMap = aes(x=x, xend=x, y=vmin, yend=vmax)
p0 = ggplot(treeSegs0$edgeDT, edgeMap) + geom_segment() + geom_segment(vertMap, data=treeSegs0$vertDT)
p1 = ggplot(treeSegs1$edgeDT, edgeMap) + geom_segment() + geom_segment(vertMap, data=treeSegs1$vertDT)
print(p0)
print(p1)
plot_tree(esophagus, "treeonly")
plot_tree(esophagus, "treeonly", ladderize="left")

Calculate weighted or unweighted (Fast) UniFrac distance for all sample pairs.

Description

This function calculates the (Fast) UniFrac distance for all sample-pairs in a phyloseq-class object.

Usage

UniFrac(physeq, weighted=FALSE, normalized=TRUE, parallel=FALSE, fast=TRUE)

## S4 method for signature 'phyloseq'
UniFrac(physeq, weighted = FALSE,
  normalized = TRUE, parallel = FALSE, fast = TRUE)

Arguments

physeq

(Required). phyloseq-class, containing at minimum a phylogenetic tree (phylo-class) and contingency table (otu_table-class). See examples below for coercions that might be necessary.

weighted

(Optional). Logical. Should use weighted-UniFrac calculation? Weighted-UniFrac takes into account the relative abundance of species/taxa shared between samples, whereas unweighted-UniFrac only considers presence/absence. Default is FALSE, meaning the unweighted-UniFrac distance is calculated for all pairs of samples.

normalized

(Optional). Logical. Should the output be normalized such that values range from 0 to 1 independent of branch length values? Default is TRUE. Note that (unweighted) UniFrac is always normalized by total branch-length, and so this value is ignored when weighted == FALSE.

parallel

(Optional). Logical. Should execute calculation in parallel, using multiple CPU cores simultaneously? This can dramatically hasten the computation time for this function. However, it also requires that the user has registered a parallel “backend” prior to calling this function. Default is FALSE. If FALSE, UniFrac will register a serial backend so that foreach::%dopar% does not throw a warning.

fast

(Optional). Logical. DEPRECATED. Do you want to use the “Fast UniFrac” algorithm? Implemented natively in the phyloseq-package. TRUE is now the only supported option. There should be no difference in the output between the two algorithms. Moreover, the original UniFrac algorithm only outperforms this implementation of fast-UniFrac if the datasets are so small (approximated by the value of ntaxa(physeq) * nsamples(physeq)) that the difference in time is inconsequential (less than 1 second). In practice it does not appear that this parameter should have ever been set to FALSE, and therefore the original UniFrac implementation perhaps never should have been supported here. For legacy code support the option is now deprecated here (the implementation was an internal function, anyway) and the fast option will remain for one release cycle before being removed completely in order to avoid causing unsupported-argument errors.

Details

UniFrac() accesses the abundance (otu_table-class) and a phylogenetic tree (phylo-class) data within an experiment-level (phyloseq-class) object. If the tree and contingency table are separate objects, suggested solution is to combine them into an experiment-level class using the phyloseq function. For example, the following code

phyloseq(myotu_table, myTree)

returns a phyloseq-class object that has been pruned and comprises the minimum arguments necessary for UniFrac().

Parallelization is possible for UniFrac calculated with the phyloseq-package, and is encouraged in the instances of large trees, many samples, or both. Parallelization has been implemented via the foreach-package. This means that parallel calls need to be preceded by 2 or more commands that register the parallel “backend”. This is acheived via your choice of helper packages. One of the simplest seems to be the doParallel package.

For more information, see the following links on registering the “backend”:

foreach package manual:

http://cran.r-project.org/web/packages/foreach/index.html

Notes on parallel computing in R. Skip to the section describing the foreach Framework. It gives off-the-shelf examples for registering a parallel backend using the doMC, doSNOW, or doMPI packages:

http://trg.apbionet.org/euasiagrid/docs/parallelR.notes.pdf

Furthermore, as of R version 2.14.0 and higher, a parallel package is included as part of the core installation, parallel-package, and this can be used as the parallel backend with the foreach-package using the adaptor package “doParallel”. http://cran.r-project.org/web/packages/doParallel/index.html

See the vignette for some simple examples for using doParallel. http://cran.r-project.org/web/packages/doParallel/vignettes/gettingstartedParallel.pdf

UniFrac-specific examples for doParallel are provided in the example code below.

Value

a sample-by-sample distance matrix, suitable for NMDS, etc.

References

http://bmf.colorado.edu/unifrac/

The main implementation (Fast UniFrac) is adapted from the algorithm's description in:

Hamady, Lozupone, and Knight, “Fast UniFrac: facilitating high-throughput phylogenetic analyses of microbial communities including analysis of pyrosequencing and PhyloChip data.” The ISME Journal (2010) 4, 17–27.

See also additional descriptions of UniFrac in the following articles:

Lozupone, Hamady and Knight, “UniFrac - An Online Tool for Comparing Microbial Community Diversity in a Phylogenetic Context.”, BMC Bioinformatics 2006, 7:371

Lozupone, Hamady, Kelley and Knight, “Quantitative and qualitative (beta) diversity measures lead to different insights into factors that structure microbial communities.” Appl Environ Microbiol. 2007

Lozupone C, Knight R. “UniFrac: a new phylogenetic method for comparing microbial communities.” Appl Environ Microbiol. 2005 71 (12):8228-35.

See Also

distance

unifrac in the picante package.

Examples

################################################################################
# Perform UniFrac on esophagus data
################################################################################
data("esophagus")
(y <- UniFrac(esophagus, TRUE))
UniFrac(esophagus, TRUE, FALSE)
UniFrac(esophagus, FALSE)
# ################################################################################
# # Now try a parallel implementation using doParallel, which leverages the 
# # new 'parallel' core package in R 2.14.0+
# # Note that simply loading the 'doParallel' package is not enough, you must
# # call a function that registers the backend. In general, this is pretty easy
# # with the 'doParallel package' (or one of the alternative 'do*' packages)
# #
# # Also note that the esophagus example has only 3 samples, and a relatively small
# # tree. This is fast to calculate even sequentially and does not warrant
# # parallelized computation, but provides a good quick example for using UniFrac()
# # in a parallel fashion. The number of cores you should specify during the
# # backend registration, using registerDoParallel(), depends on your system and
# # needs. 3 is chosen here for convenience. If your system has only 2 cores, this
# # will probably fault or run slower than necessary.
# ################################################################################
# library(doParallel)
# data(esophagus)
# # For SNOW-like functionality (works on Windows):
# cl <- makeCluster(3)
# registerDoParallel(cl)
# UniFrac(esophagus, TRUE)
# # Force to sequential backed:
# registerDoSEQ()
# # For multicore-like functionality (will probably not work on windows),
# # register the backend like this:
# registerDoParallel(cores=3)
# UniFrac(esophagus, TRUE)
################################################################################