Now open the R markdown script systemPipeChIPseq.Rmdin your R IDE (e.g. vim-r or RStudio) and run the workflow as outlined below.

Load packages and sample data

The systemPipeR package needs to be loaded to perform the analysis steps shown in this report (Girke , 2015).

library(systemPipeR)

Load workflow environment with sample data into your current working directory. The sample data are described here.

library(systemPipeRdata)
genWorkenvir(workflow="chipseq")
setwd("chipseq")
download.file("https://raw.githubusercontent.com/tgirke/GEN242/master/vignettes/12_ChIPseqWorkflow/systemPipeChIPseq.Rmd", "systemPipeChIPseq.Rmd")

In the workflow environments generated by genWorkenvir all data inputs are stored in a data/ directory and all analysis results will be written to a separate results/ directory, while the systemPipeChIPseq.Rmd script and the targets file are expected to be located in the parent directory. The R session is expected to run from this parent directory. Additional parameter files are stored under param/.

To work with real data, users want to organize their own data similarly and substitute all test data for their own data. To rerun an established workflow on new data, the initial targets file along with the corresponding FASTQ files are usually the only inputs the user needs to provide.

If applicable users can load custom functions not provided by systemPipeR. Skip this step if this is not the case.

source("systemPipeChIPseq_Fct.R")

Experiment definition provided by targets file

The targets file defines all FASTQ files and sample comparisons of the analysis workflow.

targetspath <- system.file("extdata", "targets_chip.txt", package="systemPipeR")
targets <- read.delim(targetspath, comment.char = "#")
targets[1:4,-c(5,6)]
##                   FileName SampleName Factor SampleLong SampleReference
## 1 ./data/SRR446027_1.fastq        M1A     M1  Mock.1h.A                
## 2 ./data/SRR446028_1.fastq        M1B     M1  Mock.1h.B                
## 3 ./data/SRR446029_1.fastq        A1A     A1   Avr.1h.A             M1A
## 4 ./data/SRR446030_1.fastq        A1B     A1   Avr.1h.B             M1B
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