For annotation, see the working example here: A: Affymetrix Human Genome U133 Plus 2.0 Array
Also see the biomaRt vignette (section 4.1).
Hi All,
I'm trying to analyze the data from this GEO repository with XPS and limma in R. I was able to get the probeset and transcript csv files from the Affymetrix website, but it looks like I also need two other files, a clf file and a pgf file. I'm not sure where to get these files, as I don't see anything from Affymetrix. Is it possible to create these files?
Hey,
Download the raw data CEL files and use the oligo and limma packages to process these. I do not believe you need any other files other than these [CEL files].
Here is how I processed similar arrays (your CEL files will be located in a directory called SampleFiles/):
source("http://bioconductor.org/biocLite.R")
require("limma")
#'oligo' is more suited for the Gene ST Affymetrix arrays
require("oligo")
#Disable scientific notation
options(scipen=999)
targetinfo <- readTargets("Targets.txt", sep="\t")
CELFiles <- list.celfiles("SampleFiles/", full.names = TRUE)
#Raw intensity data
project <- read.celfiles(CELFiles)
#Background correct, normalize, and calculate gene expression
project.bgcorrect.norm.avg <- rma(project, background=TRUE, normalize=TRUE, target="core")
project.bgcorrect.norm.avg.Exons <- rma(project, background=TRUE, normalize=TRUE, target="probeset")
#Perform some diagnostics on the arrays
#Generate chip images to diagnose spatial artifacts for each array and a merged boxplot of intensities
pdf("Output/ChipImageQC.pdf")
image(project)
dev.off()
pdf("Output/BoxPlotQC.pdf")
par(mar=c(5,5,5,5), cex=1, cex.axis=0.8, mfrow=c(2,1))
boxplot(project, which="all", transfo=log2, main="Raw chip fluorescent intensities", names=samplenames, las=2)
boxplot(project.bgcorrect.norm.avg, transfo=log2, main="Background-corrected, RMA normalised, log2 expression values\nAll probes", names=samplenames, las=2)
dev.off()
#Write out the normalised expression values
write.table(project.bgcorrect.norm.avg, "NormalisedCounts.GeneSummarised.tsv", sep="\t", quote=FALSE)
write.table(project.bgcorrect.norm.avg.Exons, "NormalisedCounts.ExonSummarised.tsv", sep="\t", quote=FALSE)
For annotation, see the working example here: A: Affymetrix Human Genome U133 Plus 2.0 Array
Also see the biomaRt vignette (section 4.1).
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