Barrick Lab :: ProtocolsRNASeqDifferentialExpression

---+ Analyzing RNA-Seq data for differential gene expression

---++ Materials and Software

   * Data files
      * RNA-Seq data in FASTQ format (Ex: dataset1.fastq, dataset2.fastq)
   * Genome sequence files
      * Genome sequence in FASTA format (Ex: REL606.fna)
      * Genome sequence gene annotations in GFF3 format (Ex: REL606.gff3)
   * Read mapper software
      * BWA
         * [[http://bio-bwa.sourceforge.net/][Download BWA]]
         * To build, just type "make" in the source code directory.
         * To install, move the executable "bwa" to somewhere in your $PATH, like $HOME/local/bin.
         * For usage see the [[http://bio-bwa.sourceforge.net/bwa.shtml][BWA manual]].
      * Bowtie2
         * [[http://bowtie-bio.sourceforge.net][Download Bowtie[[
         * To build, just type "make" in the source code directory.
         * Add this directory to your $PATH or move bowtie, and bowtie-* star executable to your $PATH
   * [[http://barricklab.org/breseq][breseq]]
   * R statistics package
      * [[http://cran.r-project.org/][Download and install R]]
   * Bioconductor R modules 
      * library(edgeR)
      * library(DESEQ)

---++ Commands

---+++ Align reads to reference genome

---++++ Using BWA
First, index your genome so BWA can map read to it: %BR%
<code>$bwa index REL606.fna</code> %BR%

Then, align each data set: %BR%
<code>$bwa aln REL606.fna dataset1.fastq > datasetX.sai </code> %BR%

And convert to SAM format (assumes single-end data):
<code>$bwa samse REL606.fna datasetX.sai datasetX.fastq > datasetX.sam </code> %BR%

---++++ Using bowtie2

First, index your genome so bowtie2 can map read to it: %BR%
<code>$bowtie2-build REL606.fna REL606</code> %BR%

Then, align each data set: %BR%
<code>$bowtie2 -x REL606 -U datasetX.fastq --phred33 -S REL606.sam</code> %BR%

Optionally, add the <code>--local</code> flag if your reads do not map end-to-end.

---++ Count reads mapping to genes

<code>breseq RNASEQ -f REL606.fna -r REL606.gbk -o datasetX.count.tab datasetX.sam</code> %BR%

---++ Convert alignments to BAM

And convert to BAM format (assumes single-end data):  %BR%
<code>$samtools faidx REL606.fna </code> %BR%
<code>$samtools import REL606.fna datasetX.sam datasetX.unsorted.bam </code> %BR%
<code>$samtools sort datasetX.unsorted.bam datasetX </code> %BR%
<code>$samtools index datasetX.bam </code> %BR%

Now you can use IGV to view them.

---+++ Analyze differential gene expression

library(DESEQ)
This topic: Lab > WebHome > ProtocolList > ProtocolsRNASeqDifferentialExpression
Topic revision: r3 - 2012-01-30 - JeffreyBarrick