R脚本--FeatureCounts计算reads counts 矩阵，并转化为FPKM和TPM值

代码如下：

#!/usr/bin/env Rscript 
#parse parameter
library(argparser,quietly = TRUE)
#Creat a parser
p<- arg_parser("run featureCounts and calculate FPKM/TPM")

#Add command line argumnets

p<-add_argument(p,"--bam",help="input: bam file",type="character")

p<-add_argument(p,"--gtf",help="input: gtf file",type="character")

p<-add_argument(p,"--output",help="out prefix",type="character")

#Parse the command line arguments

argv<-parse_args(p)
library(Rsubread)
library(limma)
library(edgeR)

bamFile<- argv$bam
gtfFile<- argv$gtf
nthreads<- 1
outFilePref<- argv$output

outStatsFilePath<- paste(outFilePref, '.log',sep='');
outCountsFilePath<- paste(outFilePref,'.count',sep='');

fCountsList=featureCounts(bamFile,annot.ext=gtfFile,isGTFAnnotationFile=TRUE,nthreads=nthreads,isPairedEnd=TRUE)
dgeList=DGEList(counts=fCountsList$counts,genes=fCountsList$annotation)
fpkm=rpkm(dgeList,dgeList$genes$Length)
tpm=exp(log(fpkm)-log(sum(fpkm))+log(1e6))

write.table(fCountsList$stat,outStatsFilePath,sep="\t",col.names = FALSE,row.names = FALSE,quote=FALSE)
featureCounts=cbind(fCountsList$annotation[,1],fCountsList$counts,fpkm,tpm)
colnames(featureCounts)=c('gene_id','counts','fpkm','tpm')

write.table(featureCounts,outCountsFilePath,sep="\t",col.names = TRUE,row.names = FALSE,quote = FALSE)

使用方法如下：usage: run-featurecounts.R [--] [--help] [--bam BAM]
[--gtf GTF] [--output OUTPUT]
有时候需要运行：Rscript run-featurecounts.R --bam BAM --gtf GTF --output OUTPUT
结果展示：

gene_id       counts      fpkm          tpm
Os01g0100100    372 5.48313205414791    6.2561821577044
Os01g0100200    0   0   0
Os01g0100300    0   0   0
Os01g0100400    156 3.12294044761257    3.56323431844892
Os01g0100466    0   0   0
Os01g0100500    1365    26.5755626412215    30.322370350572
Os01g0100600    117 2.58240088289187    2.94648572531943
Os01g0100650    0   0   0
Os01g0100700    3281    156.664971431348    178.752689033746

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