Package 'Cormotif'

Title: Correlation Motif Fit
Description: It fits correlation motif model to multiple studies to detect study specific differential expression patterns.
Authors: Hongkai Ji, Yingying Wei
Maintainer: Yingying Wei <[email protected]>
License: GPL-2
Version: 1.53.0
Built: 2024-10-30 05:19:36 UTC
Source: https://github.com/bioc/Cormotif

Help Index


Correlation Motif Internal functions

Description

These functions are not part of the package application programming interface and are not recommended to be used by the users.

Usage

modt.f0.loglike
modt.f1.loglike
cmfit
cmfitall
cmfitsep
cmfitfull
limmafit
generatetype

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished


Correlation Motif Fit

Description

This function fits the Correlation Motif model to multiple expression studies. It gives the fitted values for the probability distribution of each motif, the fitted values of the given correlation matrix and the posterior probability for each gene to be differentially expressed in each study.

Usage

cormotiffit(exprs,groupid,compid,K=1, tol=1e-3, max.iter=100, BIC=TRUE)

Arguments

exprs

a matrix, the expression data after normalization that is on log2 scale, each row of the matrix corresponds to a gene and each column of the matrix corresponds to a sample array.

groupid

the group label for each sample array, two arrays in the same study with same experinment condition(e.g.control)(e.g. control) have the same groupid.

compid

the study design and comparison matrix, each row of the matrix corresponds to one study with the first column being the first experinment condition and the second column being the second experinment condition.

K

a vector, each element specifing the number of motifs a model wants to fit.

tol

the relative tolerance level of error.

max.iter

maximun number of iterations.

BIC

default is BIC=TRUE, selecting the model with the lowest BIC value among all fitted models; if BIC=FALSE, selecting the model with the lowest AIC value among all fitted models.

Details

For the i^th element of KK, the function fits total number of K[i]K[i] motifs to the data. Each gene can belong to one of the K[i]K[i] possible motifs according to prior probability distribution, motif.priormotif.prior. For genes in motif jj, the probability that they are differentially expressed in study dd is motif.q(j,d)motif.q(j,d). One should indicate the groupid and compid for each study clearly.

Value

bestmotif$p.post

the posterior probability for each gene to be differentially expressed in each study for the best fitted model

bestmotif$motif.prior

fitted values of the probability distribution of different motifs for the best fitted model

bestmotif$motif.q

fitted values of the correlation motif matrix for the best fitted model

bestmotif$loglike

log-likelihood of the best fitted model

bic

the BIC values of all fitted models

aic

the AIC values of all fitted models

loglike

log-likelihood of all fitted models

Author(s)

Hongkai Ji, Yingying Wei

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished

Examples

data(simudata2)
n<-nrow(simudata2)
m<-ncol(simudata2)
#the expression data is from the second column to m
exprs.simu2<-as.matrix(simudata2[,2:m])

#prepare the group label for each sample array
data(simu2_groupid)

#prepare the design matrix for each group of samples
data(simu2_compgroup)

#fit 2 correlation motifs to the data
motif.fitted<-cormotiffit(exprs.simu2, simu2_groupid,simu2_compgroup,K=2)

All Studies Correlation Motif Fit

Description

This function assumes that a gene is either differentially expressed in all studies or is not differentially expressed in any study. It gives the fitted values for the probability distribution of motif (0,0,...0) and motif (1,1,...,1), and the posterior probability for each gene to be differentially expressed in all studies.

Usage

cormotiffitall(exprs,groupid,compid, tol=1e-3, max.iter=100)

Arguments

exprs

a matrix, the expression data after normalization that is on log2 scale, each row of the matrix corresponds to a gene and each column of the matrix corresponds to a sample array.

groupid

the group label for each sample array, two arrays in the same study with same experinment condition(e.g.control)(e.g. control) have the same groupid.

compid

the study design and comparison matrix, each row of the matrix corresponds to one study with the first column being the first experinment condition and the second column being the second experinment condition

tol

the relative tolerance level of error.

max.iter

maximun number of iterations.

Details

The difference between cormotiffitallcormotiffitall and cormotif(...,K=2,...)cormotif(...,K=2,...) is that cormotiffitallcormotiffitall forces the motif to be one of the two patterns but cormotiffitcormotiffit allows motif patterns other than (0,...,0) and (1,..,1).

Value

p.post

the posterior probability for each gene to be differentially expressed

motif.prior

fitted values of the probability distribution of motif (0,0,...0) and motif (1,1,...,1)

loglike

log-likelihood of the fitted model

Author(s)

Hongkai Ji, Yingying Wei

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished

Examples

data(simudata2)
n<-nrow(simudata2)
m<-ncol(simudata2)
#the expression data is from the second column to m
exprs.simu2<-as.matrix(simudata2[,2:m])

#prepare the group label for each sample array
data(simu2_groupid)

#prepare the design matrix for each group of samples
data(simu2_compgroup)

#fit the two motifs (0,0,...0) and (1,1,...,1) to the data
motif.fitted.all<-cormotiffitall(exprs.simu2, simu2_groupid,simu2_compgroup)

Full Model Motif Fit

Description

This function fits the data to the model with all 2D2^D possible 0-1 patterns, where DD is the number of studies.

Usage

cormotiffitfull(exprs,groupid,compid, tol=1e-3, max.iter=100)

Arguments

exprs

a matrix, the expression data after normalization that is on log2 scale, each row of the matrix corresponds to a gene and each column of the matrix corresponds to a sample array.

groupid

the group label for each sample array, two arrays in the same study with same experinment condition(e.g.control)(e.g. control) have the same groupid.

compid

the study design and comparison matrix, each row of the matrix corresponds to one study with the first column being the first experinment condition and the second column being the second experinment condition

tol

the relative tolerance level of error.

max.iter

maximun number of iterations.

Details

The difference between cormotiffitfullcormotiffitfull and cormotif(...,K=2D,...)cormotif(...,K=2^D,...) is that cormotiffitfullcormotiffitfull forces motif to be one of the those 0-1 patterns. For cormotiffitcormotiffit, the motif does not necessarily to be of either 1 or 0, such as (0,1,..,0). It could be (0.9,0.4,...,0.2).

Value

p.post

the posterior probability for each gene to be differentially expressed.

motif.prior

fitted values of the probability distribution of the 2D2^D 0-1 motifs.

loglike

log-likelihood of the fitted model.

Author(s)

Hongkai Ji, Yingying Wei

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished

Examples

data(simudata2)
n<-nrow(simudata2)
m<-ncol(simudata2)
#the expression data is from the second column to m
exprs.simu2<-as.matrix(simudata2[,2:m])

#prepare the group ID number for each sample array
data(simu2_groupid)

#prepare the design matrix for each group of samples
data(simu2_compgroup)

#fit 2^D 0-1 motifs to the data
motif.fitted.sep<-cormotiffitfull(exprs.simu2, simu2_groupid,simu2_compgroup)

Individual Study Motif Fit

Description

This function fits a mixture modified t-distribution model to each study seperately.

Usage

cormotiffitsep(exprs,groupid,compid, tol=1e-3, max.iter=100)

Arguments

exprs

a matrix, the expression data after normalization that is on log2 scale, each row of the matrix corresponds to a gene and each column of the matrix corresponds to a sample array.

groupid

the group label for each sample array, two arrays in the same study with same experinment condition(e.g.control)(e.g. control) have the same groupid.

compid

the study design and comparison matrix, each row of the matrix corresponds to one study with the first column being the first experinment condition and the second column being the second experinment condition

tol

the relative tolerance level of error.

max.iter

maximun number of iterations.

Value

p.post

the posterior probability for each gene to be differentially expressed.

motif.prior

fitted values of the probability for genes to be differentially expressed in each study, a 1D1*D vector, where DD is the number of studies

loglike

log-likelihood of the fitted model.

Author(s)

Hongkai Ji, Yingying Wei

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished

Examples

data(simudata2)
n<-nrow(simudata2)
m<-ncol(simudata2)
#the expression data is from the second column to m
exprs.simu2<-as.matrix(simudata2[,2:m])

#prepare the group ID number for each sample array
data(simu2_groupid)

#prepare the design matrix for each group of samples
data(simu2_compgroup)

#fit seperate models to each study
motif.fitted.sep<-cormotiffitsep(exprs.simu2, simu2_groupid,simu2_compgroup)

Rank genes based on statistics

Description

This function rank the genes according to the decreasing order of the given statistics.

Usage

generank(x)

Arguments

x

A GDG*D matrix of statistics, the number of rows is the number of genes and the number of columns is the number of studies.

Details

The function returns a GDG*D matrix of index of top ranked genes in each study according to the decreasing order of statistics in that study.

Author(s)

Hongkai Ji, Yingying Wei

Examples

data(simudata2)
n<-nrow(simudata2)
m<-ncol(simudata2)
#the expression data is from the second column to m
exprs.simu2<-as.matrix(simudata2[,2:m])

#prepare the group ID number for each sample array
data(simu2_groupid)

#prepare the design matrix for each group of samples
data(simu2_compgroup)

#fit 2 correlation motif to the data
motif.fitted<-cormotiffit(exprs.simu2, simu2_groupid,simu2_compgroup,K=2)
#give the gene index list according to the decreasing order of 
#posterior probability for a gene to be differentially expressed in each study 
generank(motif.fitted$bestmotif$p.post)

BIC and AIC plot

Description

This function plots BIC and AIC values for all fitted motif models.

Usage

plotIC(fitted_cormotif)

Arguments

fitted_cormotif

The object obtained from cormotiffit.

Details

The left graph is the BIC plot and the right graph is the AIC plot.

Author(s)

Hongkai Ji, Yingying Wei

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished

Examples

data(simudata2)
n<-nrow(simudata2)
m<-ncol(simudata2)
#the expression data is from the second column to \eqn{m}
exprs.simu2<-as.matrix(simudata2[,2:m])

#prepare the group ID number for each sample array
data(simu2_groupid)

#prepare the design matrix for each group of samples
data(simu2_compgroup)

#fit 2 correlation motif to the data
motif.fitted<-cormotiffit(exprs.simu2, simu2_groupid,simu2_compgroup,K=2)

plotIC(motif.fitted)

Correlation Motif plot

Description

This function plots the Correlation Motif patterns and the associated prior probability distributions.

Usage

plotMotif(fitted_cormotif,title="")

Arguments

fitted_cormotif

The object obtained from cormotiffit.

title

The title for the graph.

Details

Each row in both graphs corresponds to one motif pattern. The left graph shows the correlation motif pattern. The grey color scale of cell (k,d)(k,d) indicates the probability that motif kk is differentially expressed in study dd. Each row of the bar chart corresponds to the motif pattern in the same row of the left pattern graph. The length of the bar in the bar chart shows the number of genes of the given pattern in the dataset, which is equal to motif.fitted$bestmotif$motif.priormotif.fitted\$bestmotif\$motif.prior multiplying the number of total genes.

Author(s)

Hongkai Ji, Yingying Wei

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished

Examples

data(simudata2)
n<-nrow(simudata2)
m<-ncol(simudata2)
#the expression data is from the second column to m
exprs.simu2<-as.matrix(simudata2[,2:m])

#prepare the group ID number for each sample array
data(simu2_groupid)

#prepare the design matrix for each group of samples
data(simu2_compgroup)

#fit 2 correlation motif to the data
motif.fitted<-cormotiffit(exprs.simu2, simu2_groupid,simu2_compgroup,K=2)

plotMotif(motif.fitted)

Example dataset for Cormotif

Description

Here we present three files needed for the various Correlation Motif fit functions.

Details

simudata2 are combined from four studies sharing the same 3,000 genes, each having two experiment conditions and three samples for each condition. simudata2 saves the expression values for all genes and all sample arrays on log2 scale; simu2_groupid prepares the group label for each sample; and simu2_compgroup describes the study design

References

Ji, H., Wei, Y.,(2011) Correlation Motif. Unpublished