Last data update: 2014.03.03

R: Perform Fisher Exact Test on Methylation Data.
fishertest_cpgR Documentation

Perform Fisher Exact Test on Methylation Data.

Description

Fisher exact test is a test to calculate the statistical significance using contingency table. It was used to find the statistically significant differences in the methylation status of one particular CpG site between healthy and tumor sample. Contingency matrix was created for each CpG site. P-value was corrected for multiple testing using Benjamini-Hochberg method to calculate False Discovery Rate (FDR)

Usage

fishertest_cpg(healthy, tumor, plot = TRUE, main = "Fisher Exact Test")

Arguments

healthy

Matrix from methAlign. Also matrix where columns represents Cytosine of CpG sites and rows represents sequences.

tumor

Matrix from methAlign. Also matrix where columns represents Cytosine of CpG sites and rows represents sequences.

plot

Boolean. TRUE if need a plot after calculation. Default TRUE

main

Title of the plot. Default "Fisher Exact Test"

Value

Vector containing p-values.

Author(s)

Muhammad Ahmer Jamil, Prof. Holger Frohlich, Priv.-Doz. Dr. Osman El-Maarri

Maintainer: Muhammad Ahmer Jamil engr.ahmerjamil@gmail.com

See Also

methAlign, compare_samples

Examples

healthy = system.file("extdata", "Healthy.fasta", package = "MethTargetedNGS")
tumor = system.file("extdata", "Tumor.fasta", package = "MethTargetedNGS")
reference =  system.file("extdata", "Reference.fasta", package = "MethTargetedNGS")

healthy = methAlign(healthy,reference)
tumor = methAlign(tumor,reference)
fisherexacttest <- fishertest_cpg(healthy,tumor)

Results


R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> library(MethTargetedNGS)
Loading required package: stringr
Loading required package: seqinr
Loading required package: gplots

Attaching package: 'gplots'

The following object is masked from 'package:stats':

    lowess

Loading required package: Biostrings
Loading required package: BiocGenerics
Loading required package: parallel

Attaching package: 'BiocGenerics'

The following objects are masked from 'package:parallel':

    clusterApply, clusterApplyLB, clusterCall, clusterEvalQ,
    clusterExport, clusterMap, parApply, parCapply, parLapply,
    parLapplyLB, parRapply, parSapply, parSapplyLB

The following objects are masked from 'package:stats':

    IQR, mad, xtabs

The following objects are masked from 'package:base':

    Filter, Find, Map, Position, Reduce, anyDuplicated, append,
    as.data.frame, cbind, colnames, do.call, duplicated, eval, evalq,
    get, grep, grepl, intersect, is.unsorted, lapply, lengths, mapply,
    match, mget, order, paste, pmax, pmax.int, pmin, pmin.int, rank,
    rbind, rownames, sapply, setdiff, sort, table, tapply, union,
    unique, unsplit

Loading required package: S4Vectors
Loading required package: stats4

Attaching package: 'S4Vectors'

The following object is masked from 'package:gplots':

    space

The following objects are masked from 'package:base':

    colMeans, colSums, expand.grid, rowMeans, rowSums

Loading required package: IRanges
Loading required package: XVector

Attaching package: 'Biostrings'

The following object is masked from 'package:seqinr':

    translate

> png(filename="/home/ddbj/snapshot/RGM3/R_BC/result/MethTargetedNGS/fishertest_cpg.Rd_%03d_medium.png", width=480, height=480)
> ### Name: fishertest_cpg
> ### Title: Perform Fisher Exact Test on Methylation Data.
> ### Aliases: fishertest_cpg
> ### Keywords: Significant CpG Methylation Fisher Test
> 
> ### ** Examples
> 
> healthy = system.file("extdata", "Healthy.fasta", package = "MethTargetedNGS")
> tumor = system.file("extdata", "Tumor.fasta", package = "MethTargetedNGS")
> reference =  system.file("extdata", "Reference.fasta", package = "MethTargetedNGS")
> 
> healthy = methAlign(healthy,reference)
Time difference of 2.15 secs
> tumor = methAlign(tumor,reference)
Time difference of 1.81 secs
> fisherexacttest <- fishertest_cpg(healthy,tumor)
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>