Package 'chromVAR'

Title: Chromatin Variation Across Regions
Description: Determine variation in chromatin accessibility across sets of annotations or peaks. Designed primarily for single-cell or sparse chromatin accessibility data, e.g. from scATAC-seq or sparse bulk ATAC or DNAse-seq experiments.
Authors: Alicia Schep [aut, cre], Jason Buenrostro [ctb], Caleb Lareau [ctb], William Greenleaf [ths], Stanford University [cph]
Maintainer: Alicia Schep <[email protected]>
License: MIT + file LICENSE
Version: 1.27.0
Built: 2024-09-22 05:21:43 UTC
Source: https://github.com/bioc/chromVAR

Help Index


addGCBias

Description

Computes GC content for peaks

Usage

addGCBias(object, ...)

## S4 method for signature 'RangedSummarizedExperiment'
addGCBias(object,
  genome = GenomeInfoDb::genome(object))

## S4 method for signature 'SummarizedExperiment'
addGCBias(object, peaks,
  genome = GenomeInfoDb::genome(peaks))

Arguments

object

(Ranged)SummarizedExperiment

...

additional arguments

genome

BSgenome object, by defualt hg19

peaks

GenomicRanges with peaks, needed if object is SummarizedExperiment and not RangedSummarizedExperiment

Value

(Ranged)SummarizedExperiment object with new column in row metadata with the gc content of the peak in question

Methods (by class)

  • RangedSummarizedExperiment: method for RangedSummarizedExperiment

  • SummarizedExperiment: method for SummarizedExperiment

Examples

data(example_counts, package = "chromVAR")
# show example on small part of data 
subset_counts <- example_counts[1:500,]
library(BSgenome.Hsapiens.UCSC.hg19)
example_counts <- addGCBias(subset_counts, 
                              genome = BSgenome.Hsapiens.UCSC.hg19)

annotationMatches

Description

annotationMatches

Usage

annotationMatches(object)

annotationMatches(object) <- value

## S4 method for signature 'SummarizedExperiment'
annotationMatches(object)

## S4 replacement method for signature 'SummarizedExperiment'
annotationMatches(object) <- value

Arguments

object

SummarizedExperiment with matches slot, see details

value

logical Matrix with annotation matches

Details

Will extract matrix from the "matches", "annotationMatches", or "motif_matches" assay of a SummarizedExperiment

Value

logical matrix of annotation matches

Author(s)

Alicia Schep

Examples

# load annotation matrix; result from matchMotifs
data(mini_ix, package = "chromVAR")
matches <- annotationMatches(mini_ix)

assembleKmers

Description

function to create de novo motifs from kmers based on deviations

Usage

assembleKmers(object, threshold = 1.5, p = 0.01, progress = TRUE)

Arguments

object

kmer chromVARDeviations object

threshold

variability threshold

p

p value threshold for inclusion of kmer

progress

show progress bar?

Details

function for assembling de novo kmers from kmer deviations

Value

list with (1) motifs: de novo motif matrices, (2) seed: seed kmer for de novo motif


cbind method for chromVARDeviations

Description

cbind returns an error when applied to chromVARDeviations because results for all cells or samples should originate from same computeDeviations computation

Usage

## S4 method for signature 'chromVARDeviations'
cbind(..., deparse.level = 1)

Arguments

...

chromVARDeviations object to be combined

deparse.level

See ?base::rbind for a description of this argument.

Value

chromVARDeviations object

Author(s)

Alicia Schep

See Also

chromVARDeviations-class


chromVAR: A package for computing variability across sets of peaks.

Description

Determine variation in chromatin accessibility across sets of annotations or peaks. Designed primarily for single-cell or sparse chromatin accessibility, e.g. from scATAC-seq or sparse ATAC or DNAse-seq experiments.


chromVAR_theme

Description

theme for use with ggplot2, used by chromVAR plotting functions

Usage

chromVAR_theme(base_size = 12, base_family = "Helvetica")

Arguments

base_size

base font size

base_family

base font family

Value

ggplot2 theme

Author(s)

Alicia Schep

Examples

p <- ggplot2::qplot(1:3,1:3) + chromVAR_theme(18)

chromVARDeviations

Description

Class for storing results from computeDeviations function.

Details

This class inherits from SummarizedExperiment, and most methods for that class should work for objects of this class as well. Additionally, two accessor functions are defined for extracting bias corrected deviations (deviations) and deviation Z-scores (deviationScores)


computeDeviations

Description

Computes deviations in chromatin accessibility across sets of annotations

Usage

computeDeviations(object, annotations, ...)

## S4 method for signature 'SummarizedExperiment,SummarizedExperiment'
computeDeviations(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object))

## S4 method for signature 'SummarizedExperiment,MatrixOrmatrix'
computeDeviations(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object))

## S4 method for signature 'SummarizedExperiment,list'
computeDeviations(object, annotations,
  background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object))

## S4 method for signature 'SummarizedExperiment,missingOrNULL'
computeDeviations(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object))

## S4 method for signature 'MatrixOrmatrix,SummarizedExperiment'
computeDeviations(object,
  annotations, background_peaks, expectation = computeExpectations(object))

## S4 method for signature 'MatrixOrmatrix,MatrixOrmatrix'
computeDeviations(object, annotations,
  background_peaks, expectation = computeExpectations(object))

## S4 method for signature 'MatrixOrmatrix,list'
computeDeviations(object, annotations,
  background_peaks, expectation = computeExpectations(object))

## S4 method for signature 'MatrixOrmatrix,missingOrNULL'
computeDeviations(object, annotations,
  background_peaks, expectation = computeExpectations(object))

Arguments

object

chromVARCounts object

annotations

chromVARAnnotations object

...

additional arguments

background_peaks

(optional) background peaks matrix computed using getBackgroundPeaks, computed internally with default paramaters if not provided

expectation

(optional) expectations computed using computeExpectations, computed automatically if not provided

Details

multiprocessing using bplapply

Value

chromVARDeviations-class, which inherits from SummarizedExperiment, and has two assays: deviations and deviation scores.

Methods (by class)

  • object = SummarizedExperiment,annotations = SummarizedExperiment: object and annotations are SummarizedExperiment

  • object = SummarizedExperiment,annotations = MatrixOrmatrix: object is SummarizedExperiment, annotations are Matrix

  • object = SummarizedExperiment,annotations = list: object is SummarizedExperiment, annotations are list

  • object = SummarizedExperiment,annotations = missingOrNULL: object is SummarizedExperiment, annotations are missing

  • object = MatrixOrmatrix,annotations = SummarizedExperiment: object and annotations are SummarizedExperiment

  • object = MatrixOrmatrix,annotations = MatrixOrmatrix: object is SummarizedExperiment, annotations are Matrix

  • object = MatrixOrmatrix,annotations = list: object is SummarizedExperiment, annotations are list

  • object = MatrixOrmatrix,annotations = missingOrNULL: object is SummarizedExperiment, annotations are missing

Author(s)

Alicia Schep

See Also

computeVariability, plotVariability

Examples

# Register BiocParallel
BiocParallel::register(BiocParallel::SerialParam())
# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")
# load annotation matrix; result from matchMotifs
data(mini_ix, package = "chromVAR")

# computing deviations
dev <- computeDeviations(object = mini_counts,
                         annotations = mini_ix)

computeExpectations

Description

computeExpectations

Usage

computeExpectations(object, ...)

## S4 method for signature 'MatrixOrmatrix'
computeExpectations(object, norm = FALSE,
  group = NULL)

## S4 method for signature 'SummarizedExperiment'
computeExpectations(object, norm = FALSE,
  group = NULL)

Arguments

object

SummarizedExperiment

...

additional arguments

norm

weight all samples equally?

group

an group vector, optional

Details

By default, this function will compute the expected fraction of reads per peak as the the total fragments per peak across all samples divided by total reads in peaks in all samples. Optionally, norm can be set to TRUE and then the expectation will be the average fraction of reads in a peak across the cells. This is not recommended for single cell applications as cells with very few reads will have a large impact. Another option is to give a vector of groups, in which case the expectation will be the average fraction of reads per peak within each group. If group vector is provided and norm is set to TRUE then within each group the fraction of reads per peak is the average fraction of reads per peak in each sample. Otherwise, the within group fraction of reads per peak is based on the reads per peak within the sample divided by the total reads within each sample. The group can also be given by a length 1 character vector representing the name of a column in the colData of the input object if the input is a SummarizedExperiment

Value

vector with expected fraction of reads per peak.

Methods (by class)

  • MatrixOrmatrix: method for Matrix or matrix

  • SummarizedExperiment: method for SummarizedExperiment with counts slot

Author(s)

Alicia Schep

Examples

# First get some data
data(mini_counts, package = "chromVAR")

# Compute expectations
expectations <- computeExpectations(mini_counts)

computeVariability

Description

function to compute overall variability of motif sets across samples

Usage

computeVariability(object, bootstrap_error = TRUE, bootstrap_samples = 1000,
  bootstrap_quantiles = c(0.025, 0.975), na.rm = TRUE)

Arguments

object

output from computeDeviations

bootstrap_error

compute bootstrap confidence interval

bootstrap_samples

number of bootstrap samples to take

bootstrap_quantiles

quantiles for bootstrap

na.rm

remove NAs? default is true

Value

data.frame with columns for name, variability, bootstrap lower bound, bootstrap upper bound, raw p value, adjust p value.

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
variability <- computeVariability(mini_dev)

Accessors for the 'counts' slot of a SummarizedExperiment

Description

Accessors for the 'counts' slot of a SummarizedExperiment

Usage

## S4 method for signature 'SummarizedExperiment'
counts(object)

## S4 replacement method for signature 'SummarizedExperiment,MatrixOrmatrix'
counts(object) <- value

Arguments

object

SummarizedExperiment object

value

matrix of counts

Value

Matrix of counts

Examples

data(mini_counts, package = "chromVAR")
fragment_counts <- counts(mini_counts)

deviations

Description

Accessor for bias corrected deviations from chromVARDeviations-class object

Usage

deviations(object)

## S4 method for signature 'chromVARDeviations'
deviations(object)

Arguments

object

chromVARDeviations object

Value

matrix of bias corrected deviations

Author(s)

Alicia Schep

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
bias_corrected_deviations <- deviations(mini_dev)

deviationScores

Description

Accessor for deviation Z-scores from chromVARDeviations-class object

Usage

deviationScores(object)

## S4 method for signature 'chromVARDeviations'
deviationScores(object)

Arguments

object

chromVARDeviations object

Value

The deviationScores and deviations accessors both return matrices.

matrix of deviation Z-scores

Author(s)

Alicia Schep

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
scores <- deviationScores(mini_dev)

deviationsCovariability

Description

deviationsCovariability

Usage

deviationsCovariability(object)

Arguments

object

deviations result

Details

Returns the 'covariability' between motifs/kmers/peaksets. Covariability' is defined as covariance between Z-scores divided by variance of Z-scores for one motif/kmer/peakset (the row).

Value

'covariability' matrix

Examples

# load very small example data
data(mini_counts, package = "chromVAR")
motifs <- getJasparMotifs()
library(motifmatchr)
motif_ix <- matchMotifs(motifs, mini_counts, 
  genome = BSgenome.Hsapiens.UCSC.hg19::BSgenome.Hsapiens.UCSC.hg19)

# computing deviations
dev <- computeDeviations(object = mini_counts, 
                         annotations = motif_ix)
                         
# get covariability for just first three motifs                         
devcov <- deviationsCovariability(dev[1:3,])

deviationsTsne

Description

Perform tsne using bias corrected deviations to visualize either cell/sample similarity or motif/kmer/annotation similarity

Usage

deviationsTsne(object, threshold = 1.5, perplexity = if (what == "samples")
  30 else 8, max_iter = 1000, theta = 0.5, what = c("samples",
  "annotations"), shiny = FALSE)

Arguments

object

deviations result

threshold

variability threshold – use only deviations with variability greater than threshold

perplexity

perplexity parameter for tsne

max_iter

max iterations parameter for tsne

theta

theta parameter for tsne

what

tsne for similarity of samples or annotations?

shiny

load a shiny widget that enable you to explore perplexity and variability threshold parameter?

Value

data.frame with two columns for the two dimensions of tSNE output

Author(s)

Alicia Schep

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
                         
tsne_res <- deviationsTsne(mini_dev, threshold = 0.8, shiny = FALSE)
# setting very low variabilitiy threshold because this is mini data set
# threshold should generally be above 1
# Use plotVariability to get a sense of an appropriate threshold

differentialDeviations

Description

Function to see whether deviations differ between groups

Usage

differentialDeviations(object, groups, alternative = c("two.sided", "less",
  "greater"), parametric = TRUE)

Arguments

object

chromVARDeviations object

groups

either vector of groups or name of column in colData of object with group information

alternative

only used if there are two groups – two.sided or one sided test

parametric

use parametric test. alternatively will use kruskal wallace

Value

data.frame with p value and adjusted p value

Author(s)

Alicia Schep

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
difdev <- differentialDeviations(mini_dev, "Cell_Type")

differentialVariability

Description

Function to determine whether groups differ in variability

Usage

differentialVariability(object, groups, parametric = TRUE)

Arguments

object

chromVARDeviations object

groups

either vector of groups or name of column in colData of object with grouop information

parametric

use parametric test. alternatively will use kruskal wallace

Value

data.frame with p value and adjusted p value

Author(s)

Alicia Schep

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
difvar <- differentialVariability(mini_dev, "Cell_Type")

example_counts

Description

Very small sample data set for trying out chromVAR

Usage

data(example_counts)

Value

RangedSummarizedExperiment

Examples

data(example_counts)

filterPeaks

Description

function to get indices of peaks that pass filters

Usage

filterPeaks(object, min_fragments_per_peak = 1, non_overlapping = TRUE,
  ix_return = FALSE)

Arguments

object

SummarizedExperiment with matrix of fragment counts per peak per sample, as computed by getCounts

min_fragments_per_peak

minimum number of fragmints in peaks across all samples

non_overlapping

reduce peak set to non-overlapping peaks, see details

ix_return

return indices of peaks to keep instead of subsetted counts object

Details

if non_overlapping is set to true, when peaks overlap the overlapping peak with lower counts is removed

Value

vector of indices, representing peaks that should be kept

Author(s)

Alicia Schep

See Also

getPeaks, filterSamples, getCounts

Examples

data(example_counts, package = "chromVAR")

counts_filtered <- filterSamples(example_counts, min_depth = 1500,
                                  min_in_peaks = 0.15, shiny = FALSE)
counts_filtered <- filterPeaks(example_counts)

filterSamples

Description

function to get indices of samples that pass filtters

Usage

filterSamples(object, min_in_peaks = NULL, min_depth = NULL,
  shiny = interactive(), ix_return = FALSE)

Arguments

object

SummarizedExperiment with matrix of fragment counts per peak per sample, as computed by getCounts

min_in_peaks

minimum fraction of samples within peaks

min_depth

minimum library size

shiny

make shiny gadget?

ix_return

return indices of sample to keep instead of subsetted counts object

Details

If unspecified, min_in_peaks and min_depth cutoffs will be estimated based on data. min_in_peaks is set to 0.5 times the median proportion of fragments in peaks. min_depth is set to the maximum of 500 or 10 median library size.

Value

indices of samples to keep

See Also

getCounts, getPeaks, filterPeaks

Examples

data(example_counts, package = "chromVAR")

counts_filtered <- filterSamples(example_counts, min_depth = 1500,
                                  min_in_peaks = 0.15, shiny = FALSE)

filterSamplesPlot

Description

plot filtering of samples

Usage

filterSamplesPlot(object, min_in_peaks = NULL, min_depth = NULL,
  use_plotly = interactive())

Arguments

object

SummarizedExperiment with matrix of fragment counts per peak per sample, as computed by getCounts

min_in_peaks

minimum fraction of samples within peaks

min_depth

minimum library size

use_plotly

make interactive plot?

Details

If unspecified, min_in_peaks and min_depth cutoffs will be estimated based on data. min_in_peaks is set to 0.5 times the median proportion of fragments in peaks. min_depth is set to the maximum of 500 or 10 median library size.

Value

indices of samples to keep

See Also

getCounts, getPeaks, filterPeaks

Examples

data(example_counts, package = "chromVAR")

counts_filtered <- filterSamples(example_counts, min_depth = 1500,
                                  min_in_peaks = 0.15, shiny = FALSE)
counts_filtered_plot <- filterSamplesPlot(counts_filtered, 
                                          min_in_peaks = 0.15,
                                          min_depth = 1500, 
                                          use_plotly = FALSE)

getAnnotationCorrelation

Description

getAnnotationCorrelation

Usage

getAnnotationCorrelation(object, annotations, ...)


  ## S4 method for signature 'SummarizedExperiment,SummarizedExperiment'
getAnnotationCorrelation(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object), variabilities = NULL)


  ## S4 method for signature 'SummarizedExperiment,MatrixOrmatrix'
getAnnotationCorrelation(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object), variabilities = NULL)

## S4 method for signature 'SummarizedExperiment,list'
getAnnotationCorrelation(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object), variabilities = NULL)


  ## S4 method for signature 'MatrixOrmatrix,SummarizedExperiment'
getAnnotationCorrelation(object,
  annotations, background_peaks, expectation = computeExpectations(object),
  variabilities = NULL)

## S4 method for signature 'MatrixOrmatrix,MatrixOrmatrix'
getAnnotationCorrelation(object,
  annotations, background_peaks, expectation = computeExpectations(object),
  variabilities = NULL)

## S4 method for signature 'MatrixOrmatrix,list'
getAnnotationCorrelation(object, annotations,
  background_peaks, expectation = computeExpectations(object),
  variabilities = NULL)

Arguments

object

result from computeDeviations

annotations

SummarizedExperiment of annotation matches

...

additional arguments

background_peaks

optional, matrix of background peaks

expectation

optional, expected fraction of reads per peak, as computed by computeExpectations

variabilities

optional, variabilities computed from computeVariability

Details

should only be run on small number of motifs/kmers/peaksets (very slow!)

Value

correlation matrix

Methods (by class)

  • object = SummarizedExperiment,annotations = SummarizedExperiment: object and annotations are SummarizedExperiment

  • object = SummarizedExperiment,annotations = MatrixOrmatrix: object is SummarizedExperiment, annotations are Matrix

  • object = SummarizedExperiment,annotations = list: object is SummarizedExperiment, annotations are list

  • object = MatrixOrmatrix,annotations = SummarizedExperiment: object and annotations are SummarizedExperiment

  • object = MatrixOrmatrix,annotations = MatrixOrmatrix: object is SummarizedExperiment, annotations are Matrix

  • object = MatrixOrmatrix,annotations = list: object is SummarizedExperiment, annotations are list


getAnnotations

Description

getAnnotations

Usage

getAnnotations(annotations, ...)

## S4 method for signature 'GRangesList'
getAnnotations(annotations, rowRanges, ...)

## S4 method for signature 'MatrixOrmatrix'
getAnnotations(annotations, ...)

## S4 method for signature 'data.frame'
getAnnotations(annotations, ...)

## S4 method for signature 'list'
getAnnotations(annotations, npeaks = NULL, ...)

## S4 method for signature 'character'
getAnnotations(annotations, rowRanges, column = NULL,
  ...)

Arguments

annotations

matrix, Matrix, or data.frame of fragment counts, or SummarizedExperiment with counts assays, see details

...

additional arguments to pass to SummarizedExperiment

rowRanges

GenomicRanges or GenomicRangesList or RangedSummarizedExperiment

npeaks

number of peaks

column

column of bed file with annotation names, see details

Value

SummarizedExperiment object with 'matches' assay

Methods (by class)

  • GRangesList: get annotation matrix from GRangesList

  • MatrixOrmatrix: get annotation matrix from Matrix or matrix

  • data.frame: get annotation matrix from data.frame

  • list: get annotation matrix from list

  • character: get annotations from bed files

Author(s)

Alicia Schep

Examples

# First get example counts
data(mini_counts, package = "chromVAR")

# Get annotations from genomic ranges list
library(GenomicRanges)
library(SummarizedExperiment)
my_annotation_granges <- GRangesList(GRanges("chr1", 
                                             ranges = IRanges(start = 
                                             c(566763,805090), width = 8)),
                                     GRanges("chr1", ranges = IRanges(start =
                                               c(566792,895798), width = 8)))
anno_ix <- getAnnotations(my_annotation_granges, 
                           rowRanges = rowRanges(mini_counts))

getAnnotationSynergy

Description

getAnnotationSynergy

Usage

getAnnotationSynergy(object, annotations, ...)


  ## S4 method for signature 'SummarizedExperiment,SummarizedExperiment'
getAnnotationSynergy(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object), variabilities = NULL,
  nbg = 25)

## S4 method for signature 'SummarizedExperiment,MatrixOrmatrix'
getAnnotationSynergy(object,
  annotations, background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object), variabilities = NULL,
  nbg = 25)

## S4 method for signature 'SummarizedExperiment,list'
getAnnotationSynergy(object, annotations,
  background_peaks = getBackgroundPeaks(object),
  expectation = computeExpectations(object), variabilities = NULL,
  nbg = 25)

## S4 method for signature 'MatrixOrmatrix,SummarizedExperiment'
getAnnotationSynergy(object,
  annotations, background_peaks, expectation = computeExpectations(object),
  variabilities = NULL, nbg = 25)

## S4 method for signature 'MatrixOrmatrix,MatrixOrmatrix'
getAnnotationSynergy(object,
  annotations, background_peaks, expectation = computeExpectations(object),
  variabilities = NULL, nbg = 25)

## S4 method for signature 'MatrixOrmatrix,list'
getAnnotationSynergy(object, annotations,
  background_peaks, expectation = computeExpectations(object),
  variabilities = NULL, nbg = 25)

Arguments

object

result from computeDeviations

annotations

SummarizedExperiment of annotation matches

...

additional arguments

background_peaks

optional, matrix of background peaks

expectation

optional, expected fraction of reads per peak, as computed by computeExpectations

variabilities

optional, variabilities computed from computeVariability

nbg

number of background iterations

Details

should only be run on small number of motifs/kmers/peaksets (very slow!)

Value

synergy matrix

Methods (by class)

  • object = SummarizedExperiment,annotations = SummarizedExperiment: object and annotations are SummarizedExperiment

  • object = SummarizedExperiment,annotations = MatrixOrmatrix: object is SummarizedExperiment, annotations are Matrix

  • object = SummarizedExperiment,annotations = list: object is SummarizedExperiment, annotations are list

  • object = MatrixOrmatrix,annotations = SummarizedExperiment: object and annotations are SummarizedExperiment

  • object = MatrixOrmatrix,annotations = MatrixOrmatrix: object is SummarizedExperiment, annotations are Matrix

  • object = MatrixOrmatrix,annotations = list: object is SummarizedExperiment, annotations are list


getBackgroundPeaks

Description

Function to get a set of background peaks for each peak based on GC content and # of fragments across all samples

Usage

getBackgroundPeaks(object, ...)

## S4 method for signature 'SummarizedExperiment'
getBackgroundPeaks(object,
  bias = rowData(object)$bias, niterations = 50, w = 0.1, bs = 50)

## S4 method for signature 'RangedSummarizedExperiment'
getBackgroundPeaks(object,
  bias = rowRanges(object)$bias, niterations = 50, w = 0.1, bs = 50)

## S4 method for signature 'MatrixOrmatrix'
getBackgroundPeaks(object, bias, niterations = 50,
  w = 0.1, bs = 50)

Arguments

object

fragment counts as SummarizedExperiment, RangedSummarized, Matrix, or matrix

...

addtional arguments

bias

vector of values for some bias signal for each row of object

niterations

number of background peaks to sample

w

parameter controlling similarity of background peaks

bs

bin size parameter

Details

Background peaks are chosen by sampling peaks based on similarity in GC content and # of fragments across samples using the Mahalanobis distance. The w paramter controls how similar background peaks should be. The bs parameter controls the precision with which the similarity is computed; increasing bs will make the function run slower. Sensible default parameters are chosen for both.

Value

matrix with one row per peak and one column per iteration. values in a row represent indices of background peaks for the peak with that index

Methods (by class)

  • SummarizedExperiment: method for SummarizedExperiment

  • RangedSummarizedExperiment: method for RangedSummarizedExperiment

  • MatrixOrmatrix: method for Matrix or matrix

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")

# get background peaks
bgpeaks <- getBackgroundPeaks(mini_counts)

getCisGroups

Description

Function for grouping peaks based on proximity along chromosomes

Usage

getCisGroups(object, ...)

## S4 method for signature 'RangedSummarizedExperiment'
getCisGroups(object, grpsize = 25,
  stepsize = 10)

## S4 method for signature 'GenomicRanges'
getCisGroups(object, grpsize = 25, stepsize = 10)

Arguments

object

GenomicRanges or RangedSummarizedExperiment

...

additional arguments

grpsize

number of peaks to include in each grouop

stepsize

number of peaks between each new set of groups

Value

SummarizedExperiment with annotationMatches assay storing which peaks belong to which groups

Methods (by class)

  • RangedSummarizedExperiment: method for RangedSummarizedExperiment

  • GenomicRanges: method for GenomicRanges

Author(s)

Alicia Schep

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")
mini_counts <- sort(mini_counts)
cisg <- getCisGroups(mini_counts)

getCounts

Description

makes matrix of fragment counts in peaks using one or multiple bam or bed files

Usage

getCounts(alignment_files, peaks, paired, by_rg = FALSE, format = c("bam",
  "bed"), colData = NULL)

Arguments

alignment_files

filenames for bam or bed files with aligned reads

peaks

GRanges object with peaks

paired

paired end data?

by_rg

use RG tags in bam to separate groups?

format

bam or bed? default is bam

colData

sample annotation DataFrame

Value

RangedSummarizedExperiment-class object

See Also

getSampleDepths, getPeaks, filterSamples

Examples

# First we'll read in some peaks
peaks_file <- system.file("extdata", "test_bed.txt", package = "chromVAR")
test_peaks <- getPeaks(peaks_file, sort = TRUE)

# With single bam with RG tags (can also give multiple bams with RG)
test_rg <- system.file("extdata", "test_RG.bam", package = "chromVAR")
test_counts <- getCounts(test_rg, peaks = test_peaks, by_rg = TRUE, 
                          paired = TRUE, 
                          colData = S4Vectors::DataFrame(condition ="A"))
                          

# Multiple bams without RG tags
test_bam1 <- system.file("extdata", "test_single1.bam", package = "chromVAR")
test_bam2 <- system.file("extdata", "test_single2.bam", package = "chromVAR")
test_bam3 <- system.file("extdata", "test_single3.bam", package = "chromVAR")
test_counts2 <- getCounts(c(test_bam1, test_bam2,test_bam3), 
                           peaks = test_peaks, by_rg = FALSE, 
                           paired = TRUE, 
                           colData = S4Vectors::DataFrame(celltype = 
                                                          c("A","B","C"))) 
                           
# Bed file with reads (can give multiple bed files, here we will just read 1)
test_bed <- system.file("extdata", "test_reads.bed", package = "chromVAR")
test_counts3 <- getCounts(test_bed, test_peaks, by_rg = FALSE, 
                           paired = FALSE, 
                           format = "bed")

getFragmentsPerPeak

Description

getFragmentsPerPeak

Usage

getFragmentsPerPeak(object)

## S4 method for signature 'SummarizedExperiment'
getFragmentsPerPeak(object)

## S4 method for signature 'MatrixOrmatrix'
getFragmentsPerPeak(object)

Arguments

object

SummarizedExperiment, matrix, or Matrix object

Value

vector with sum across rows of counts assay within chromVARCounts

Methods (by class)

  • SummarizedExperiment: method for SummarizedExperiment object with counts assay

  • MatrixOrmatrix: method for Matrix or matrix object

See Also

getFragmentsPerSample, getTotalFragments

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")

frags_per_peak <- getFragmentsPerPeak(mini_counts)

getFragmentsPerSample

Description

getFragmentsPerSample

Usage

getFragmentsPerSample(object)

## S4 method for signature 'SummarizedExperiment'
getFragmentsPerSample(object)

## S4 method for signature 'MatrixOrmatrix'
getFragmentsPerSample(object)

Arguments

object

SummarizedExperiment, matrix, or Matrix object

Value

vector with sum across columns of counts assay within chromVARCounts

Methods (by class)

  • SummarizedExperiment: method for SummarizedExperiment object with counts assay

  • MatrixOrmatrix: method for Matrix or matrix object

See Also

getFragmentsPerPeak, getTotalFragments

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")
frags_per_sample <- getFragmentsPerSample(mini_counts)

getJasparMotifs

Description

Function to get motifs from JASPAR database

Usage

getJasparMotifs(species = "Homo sapiens", collection = "CORE", ...)

Arguments

species

Which species? use eithe jaspar code or latin name. default is 'Homo sapiens'

collection

Which collection to use? default is 'CORE'

...

additional arguments to opts for getMatrixSet

Details

Simply a wrapper function for getMatrixSet that calls JASPAR2016 database using JASPAR2016

Value

PFMatrixList

Examples

motifs <- getJasparMotifs()

getPeaks

Description

Read in peaks from a bed file.

Usage

getPeaks(filename, extra_cols = c(), sort_peaks = FALSE)

Arguments

filename

filename of bed file

extra_cols

extra columns to read in beyond first three

sort_peaks

sort the peaks?

Details

As in standard definition of bed file, first column is assumed to be chromosome, second is assumed to be start of peak (0-based), and third is assumed to be end of peak (1-based). Note that in output GenomicRanges output, start and end indices are both 1-based. Extra columns can be added as metadata or strand information if provided, but the user must indicate column index and name using named vector for extra_cols.

Value

GenomicRanges containing peaks from file

See Also

getCounts, filterPeaks, readNarrowpeaks

Examples

peaks_file <- system.file("extdata", "test_bed.txt", package = "chromVAR")
peaks <- getPeaks(peaks_file, sort = TRUE)

getPermutedData

Description

Function to get permuted data while maintaining biases

Usage

getPermutedData(object, niterations = 10, w = 0.1, bs = 50)

Arguments

object

SummarizedExperiment

niterations

number of background peaks to sample

w

parameter controlling similarity of background peaks

bs

bin size parameter

Details

Replaces the counts at a given peak with the count from another peak with similar GC content and average accessibility

Value

new SummarizedExperiment with addition assays representing permuted version of counts

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")

# get background peaks
perm_counts <- getPermutedData(mini_counts, niterations = 2)

getSampleCorrelation

Description

Get correlation between samples based on bias corrected deviations

Usage

getSampleCorrelation(object, threshold = 1.5)

Arguments

object

deviations result

threshold

threshold for variability

Details

This function will compute the correlation between samples based on the normalized deviations. It will first remove correlated motifs/peak sets. Then the pearson correlation coefficient will be computed and returned.

Value

correlation matrix between samples

Author(s)

Alicia Schep

See Also

getSampleDistance

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
sample_cor <- getSampleCorrelation(mini_dev, threshold = 0.8)  
# setting very low variabilitiy threshold because this is mini data set
# threshold should generally be above 1
# Use plotVariability to get a sense of an appropriate threshold
# As this is mini data set, results probably not meaningful!

getSampleDepths

Description

makes vector of read depths in bam files or RG groups within bam files

Usage

getSampleDepths(alignment_files, paired = TRUE, by_rg = FALSE,
  format = c("bam", "bed"))

Arguments

alignment_files

filenames for bam or bed file(s) with aligned reads

paired

paired end data?

by_rg

use RG tags to separate groups?

format

bam or bed format? default is bam

Value

numeric vector

See Also

getCounts, filterSamples

Examples

# With single bam with RG tags (can also give multiple bams with RG)
test_rg <- system.file("extdata", "test_RG.bam", package = "chromVAR")
test_counts <- getSampleDepths(test_rg,  by_rg = TRUE, 
                          paired = TRUE)
                          

# Multiple bams without RG tags
test_bam1 <- system.file("extdata", "test_single1.bam", package = "chromVAR")
test_bam2 <- system.file("extdata", "test_single2.bam", package = "chromVAR")
test_bam3 <- system.file("extdata", "test_single3.bam", package = "chromVAR")
test_counts2 <- getSampleDepths(c(test_bam1, test_bam2,test_bam3), 
                           by_rg = FALSE, 
                           paired = TRUE)

getSampleDistance

Description

Get distance between samples based on bias corrected deviations

Usage

getSampleDistance(object, threshold = 1.5, initial_dims = 50,
  distance_function = dist)

Arguments

object

deviations result

threshold

threshold for variability

initial_dims

initial dimentions for preliminary dimensionality reduction via pca

distance_function

distance function to use

Details

This function will compute the distance between samples based on the normalized deviations. It will first remove correlated motifs / peak sets. Then the dimensionality will be further reduced via PCA if the number of dimensions exceeds initial_dims. Then the supplied distance_function will be used.

Value

dist object for distance between samples

Author(s)

Alicia Schep

See Also

getSampleCorrelation

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
sample_dist <- getSampleDistance(mini_dev, threshold = 0.8)  
# setting very low variabilitiy threshold because this is mini data set
# threshold should generally be above 1
# Use plotVariability to get a sense of an appropriate threshold
# As this is mini data set, results  not meaningful!

getTotalFragments

Description

getTotalFragments

Usage

getTotalFragments(object)

## S4 method for signature 'SummarizedExperiment'
getTotalFragments(object)

## S4 method for signature 'MatrixOrmatrix'
getTotalFragments(object)

Arguments

object

SummarizedExperiment, matrix, or Matrix object

Value

sum of all counts within object

Methods (by class)

  • SummarizedExperiment: method for SummarizedExperiment object with counts assay

  • MatrixOrmatrix: method for Matrix or matrix object

See Also

getFragmentsPerSample, getFragmentsPerPeak

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")
total_frags <- getTotalFragments(mini_counts)

makeBiasBins

Description

Makes bins based on fragment counts

Usage

makeBiasBins(object, ...)

## S4 method for signature 'SummarizedExperiment'
makeBiasBins(object,
  bias = rowData(object)$bias, nbins = 25, frac = 0.3)

## S4 method for signature 'RangedSummarizedExperiment'
makeBiasBins(object,
  bias = rowRanges(object)$bias, nbins = 25, frac = 0.3)

## S4 method for signature 'MatrixOrmatrix'
makeBiasBins(object, bias, nbins = 25,
  frac = 0.3)

Arguments

object

fragment counts stored as RangedSummarizedExperiment, SummarizedExperiment, matrix, or Matrix

...

addtional arguments

bias

vector of some bias signal (usually gc content) for each row of object

nbins

number of bins for each category, see Details

frac

fraction of peaks within given bin to select randomly

Details

Will create nbins * 3 annotations based on sampling from peaks with a certain fragment count, fragment count, or fragment count & bias.

Value

SummarizedExperiment storing bias bins annotation

Methods (by class)

  • SummarizedExperiment: method for SummarizedExperiment

  • RangedSummarizedExperiment: method for RangedSummarizedExperiment

  • MatrixOrmatrix: method for Matrix or matrix

Author(s)

Alicia Schep

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")
bb <- makeBiasBins(mini_counts)

makePermutedSets

Description

Makes annotations sets with similar bias to input sets

Usage

makePermutedSets(object, annotations, ...)

## S4 method for signature 'SummarizedExperiment,SummarizedExperiment'
makePermutedSets(object,
  annotations, bias = rowData(object)$bias, window = 10)


  ## S4 method for signature 'RangedSummarizedExperiment,SummarizedExperiment'
makePermutedSets(object,
  annotations, bias = rowRanges(object)$bias, window = 10)

## S4 method for signature 'MatrixOrmatrix,SummarizedExperiment'
makePermutedSets(object,
  annotations, bias, window = 10)

## S4 method for signature 'SummarizedExperiment,MatrixOrmatrix'
makePermutedSets(object,
  annotations, bias = rowData(object)$bias, window = 10)

## S4 method for signature 'RangedSummarizedExperiment,MatrixOrmatrix'
makePermutedSets(object,
  annotations, bias = rowRanges(object)$bias, window = 10)

## S4 method for signature 'MatrixOrmatrix,MatrixOrmatrix'
makePermutedSets(object, annotations,
  bias, window = 10)

## S4 method for signature 'SummarizedExperiment,list'
makePermutedSets(object, annotations,
  bias = rowData(object)$bias, window = 10)

## S4 method for signature 'RangedSummarizedExperiment,list'
makePermutedSets(object,
  annotations, bias = rowRanges(object)$bias, window = 10)

## S4 method for signature 'MatrixOrmatrix,list'
makePermutedSets(object, annotations, bias,
  window = 10)

Arguments

object

fragment counts stored as RangedSummarizedExperiment, SummarizedExperiment, matrix, or Matrix

annotations

annotations as SummarizedExperiment, matrix, or list

...

additional arguments

bias

vector of some bias signal (usually gc content) for each row of object

window

number of nearest neighbors to consider

Details

Will create nbins * 3 annotations based on sampling from peaks with a certain fragment count, fragment count, or fragment count & bias.

Value

SummarizedExperiment storing bias bins annotation

Methods (by class)

  • object = SummarizedExperiment,annotations = SummarizedExperiment: method for SummarizedExperiment and SummarizedExperiment

  • object = RangedSummarizedExperiment,annotations = SummarizedExperiment: method for RangedSummarizedExperiment and SummarizedExperiment

  • object = MatrixOrmatrix,annotations = SummarizedExperiment: method for Matrix or matrix and SummarizedExperiment

  • object = SummarizedExperiment,annotations = MatrixOrmatrix: method for SummarizedExperiment and MatrixOrmatrix

  • object = RangedSummarizedExperiment,annotations = MatrixOrmatrix: method for RangedSummarizedExperiment and MatrixOrmatrix

  • object = MatrixOrmatrix,annotations = MatrixOrmatrix: method for Matrix/matrix and Matrix/matrix

  • object = SummarizedExperiment,annotations = list: method for SummarizedExperiment and list

  • object = RangedSummarizedExperiment,annotations = list: method for RangedSummarizedExperiment and list

  • object = MatrixOrmatrix,annotations = list: method for Matrix or matrix and list

Author(s)

Alicia Schep

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")
data(example_motifs, package = "motifmatchr")
library(motifmatchr)
library(BSgenome.Hsapiens.UCSC.hg19)
motif_ix <- matchMotifs(example_motifs, mini_counts, 
                         genome = BSgenome.Hsapiens.UCSC.hg19)

perm_sets <- makePermutedSets(mini_counts, motif_ix)

matchKmers

Description

Find kmer matches in the DNA string-based subject

Usage

matchKmers(k, subject, ...)

## S4 method for signature 'character,DNAStringSet'
matchKmers(k, subject, out = c("matches",
  "positions"), ranges = NULL)

## S4 method for signature 'character,character'
matchKmers(k, subject, out = c("matches",
  "positions"), ranges = NULL)

## S4 method for signature 'character,DNAString'
matchKmers(k, subject, out = c("matches",
  "positions"), ranges = NULL)

## S4 method for signature 'character,GenomicRanges'
matchKmers(k, subject,
  genome = GenomeInfoDb::genome(subject), out = c("matches", "positions"))

## S4 method for signature 'character,RangedSummarizedExperiment'
matchKmers(k, subject, ...)

## S4 method for signature 'numeric,ANY'
matchKmers(k, subject, ...)

## S4 method for signature 'DNAStringSet,ANY'
matchKmers(k, subject, ...)

## S4 method for signature 'DNAString,ANY'
matchKmers(k, subject, ...)

Arguments

k

k

subject

either GenomicRanges, DNAStringSet, DNAString, or character vector

...

additional arguments

out

what to return? see details

ranges

if subject is not GenomicRanges, ranges to use when out is positions

genome

BSgenome object, only used if subect is GenomicRanges

Details

Can either return a SummarizedExperiment with just sparse matrix with values set to 1 for a match (if return == 'matches'), or a GenomicRanges object with all the positions of matches

Value

SummarizedExperiment with matches assay storing which peaks contain which kmers

Methods (by class)

  • k = character,subject = DNAStringSet: For DNAStringSet Objects

  • k = character,subject = character: For character strings

  • k = character,subject = DNAString: For DNA String objects

  • k = character,subject = GenomicRanges: For GenomicRanges

  • k = character,subject = RangedSummarizedExperiment: For RangedSummarizedExperiment (containing GRanges in rowRanges)

  • k = numeric,subject = ANY: Catch-all for other un-documented types

  • k = DNAStringSet,subject = ANY: Catch-all for other un-documented types with DNAStringSet

  • k = DNAString,subject = ANY: Catch-all for other un-documented types with DNAString

See Also

getAnnotations, computeDeviations

Examples

# Load very small example counts (already filtered)
data(mini_counts, package = "chromVAR")

# Get peak-kmer annotation matrix for 6mers
library(BSgenome.Hsapiens.UCSC.hg19)
kmer_ix <- matchKmers(6, mini_counts, 
                       genome = BSgenome.Hsapiens.UCSC.hg19)

mini_counts

Description

Tiny sample data set for chromVAR funtion examples

Usage

data(mini_counts)

Value

RangedSummarizedExperiment

See Also

mini_dev, mini_ix

Examples

data(mini_counts)

mini_dev

Description

Tiny sample chromVARDeviations object resulting from computeDeviations Result from running computeDeviations(mini_counts, mini_ix) on mini_ix and mini_counts data from this package

Usage

data(mini_dev)

Value

chromVARDeviations-class

See Also

computeDeviations, mini_counts, mini_ix

Examples

data(mini_dev)

mini_ix

Description

Tiny sample annotation object for use in chromVAR examples Result from running matchMotifs(example_motifs,mini_counts,"hg19) on example_motifs from motifmatchr package and mini_counts from this package

Usage

data(mini_ix)

Value

RangedSummarizedExperiment

See Also

mini_counts, mini_dev

Examples

data(mini_ix)

plotDeviationsTsne

Description

plots sample similarity tsne

Usage

plotDeviationsTsne(object, tsne, var_df = NULL, sample_column = NULL,
  annotation_name = NULL, shiny = interactive())

Arguments

object

deviations result object

tsne

result from deviationsTsne

var_df

variability result

sample_column

column name for sample data – colData(object) – to be used for coloring points

annotation_name

name of chromVAR annotation for coloring points

shiny

return shiny app? otherwise return static plots

Value

shiny app or plots

Author(s)

Alicia Schep


plotKmerMismatch

Description

plotKmerMismatch

Usage

plotKmerMismatch(kmer, cov_mat, pval = 0.01)

Arguments

kmer

kmer, e.g. 'AAAAAAA'

cov_mat

result from deviationsCovariability

pval

p value threshold

Value

A plot


plotVariability

Description

plot variability of motifs/etc

Usage

plotVariability(variability, xlab = "Sorted TFs", n = 3,
  labels = variability$name, use_plotly = interactive())

Arguments

variability

output from computeVariability

xlab

label for x-axis (default is 'Sorted TFs')

n

number of toppoints to label?

labels

names of sets. if not given, uses rownames of variability

use_plotly

make plot interactive (using plotly)

Value

ggplot or plotly object, depending on whether use_plotly is TRUE

Author(s)

Alicia Schep

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
variability <- computeVariability(mini_dev)
var_plot <- plotVariability(variability, use_plotly = FALSE)

pwmDistance

Description

computes distance between every pwm in a list or between pwms in one list with pwms in another

Usage

pwmDistance(x, y = NULL, min_overlap = 5)

Arguments

x

list of pwms or pfms, see Details

y

list of pwms or pfms, see Details

min_overlap

minimum number of basepairs overlapping between motifs

Details

The format of x and y should be a PWMatrixList or PFMatrixList or a list of matrices with rows corresponding to "A","C","G","T" and columns summing to 1.

Value

a list with three matrices- 'dist' has the distance between each pair of motifs, 'strand' has the strand of the motif for the match, and 'offset' has the offset between the motifs.

Examples

motifs <- getJasparMotifs()
library(TFBSTools)
pwm_dists <- pwmDistance(toPWM(motifs[[1]]), toPWM(motifs[[2]]))

rbind method chromVARDeviations

Description

Concatenates chromVARDeviations results for different sets of annotations

Usage

## S4 method for signature 'chromVARDeviations'
rbind(..., deparse.level = 1)

Arguments

...

chromVARDeviations object to be combined

deparse.level

See ?base::rbind for a description of this argument.

Value

chromVARDeviations object

Author(s)

Alicia Schep

See Also

chromVARDeviations-class

Examples

# Load very small example results from computeDeviations
data(mini_dev, package = "chromVAR")
doubledev <- rbind(mini_dev, mini_dev) #concatenate two of the same tother

readNarrowpeaks

Description

Reads in peaks in narrowpeaks format, as output by macs2. Uses summit as center of peak, and makes peak the given 'width'. By default removes overlapping peaks to get set of peaks with no overlaps

Usage

readNarrowpeaks(filename, width = 500, non_overlapping = TRUE)

Arguments

filename

filename

width

desired width of peaks

non_overlapping

remove overlapping peaks

Value

GRanges-class