Hello everyone,

I'm working with data that was performed using Agilent-014850 Whole Human Genome Microarray 4x44K G4112F arrays and the One Color Quick Amp Labeling Kit (Agilent Technologies, Santa Clara, USA).

I'm trying to set up a code in R:

#Load limma
library(limma)

#Set-up
targetinfo <- readTargets("Targets.txt",row.names="FileName",sep="")

#Read files
project <- read.maimages(targetinfo,source="agilent", green.only=TRUE)

#Background correction
project.bgc <- backgroundCorrect(project, method="normexp", offset=16)

#Normalize the data with the 'quantile' method for 1-color
project.NormData <-normalizeBetweenArrays(project.bgc,method="quantile")

#Create the study design and comparison model
design <- paste(targetinfo$Target, sep="")
design <- factor(design)
comparisonmodel <- model.matrix(~0+design)
colnames(comparisonmodel) <- levels(design)
#Checking the experimental design
design
comparisonmodel

project.fit <- lmFit(project.NormData, comparisonmodel)

#When I used > project.fit <- lmFit(project.NormData$M, comparisonmodel)
Error in array(x, c(length(x), 1L), if (!is.null(names(x))) list(names(x),  : 
'data' must be of a vector type, was 'NULL'


#So, I used without a $M 
project.fit <- lmFit(project.NormData,comparisonmodel)
  

#Applying the empirical Bayes method
project.fit.eBayes <- eBayes(project.fit)
names(project.fit.eBayes)

#Make individual contrasts and fit the new model
CaseControl <- makeContrasts(CaseControl="D0A-Control", levels=comparisonmodel)
CaseControl.fitmodel <- contrasts.fit(project.fit.eBayes, CaseControl)
CaseControl.fitmodel.eBayes <- eBayes(CaseControl.fitmodel)

#Filtering Results
 nrow(topTable(CaseControl.fitmodel.eBayes, coef="CaseControl", number=99999, lfc=2))
 probeset.list <- topTable(CaseControl.fitmodel.eBayes, "CaseControl", number=99999, adjust.method="BH", sort.by="P", lfc=2)

#To save results
write.table(probeset.list, "results.txt", sep="\t", quote=FALSE)

Well, now it seems correct, and you guys what do you think?

Best regards,

Leite