Entering edit mode
Dawn
▴
10
@dawn-4206
Last seen 8.1 years ago
Hi,
I'm using Limma for DE of microarray data. But logFC values in the topTable are not correct, and actually I got the minus values of the two conditions C1 and C2: mean(C1)-mean(C2).
>head(dat_mean) mock_EGF_mean1 mock_EGF_mean2 mock_no_mean1 mock_no_mean2 p63(Phospho-Ser455) 10720 12198 8806 6693 p53(Phospho-Thr81) 24904 26344 24109 23845 p53(Phospho-Thr18) 24353 25907 10325 13047 WT_EGF_mean1 WT_EGF_mean2 WT_no_mean1 WT_no_mean2 p63(Phospho-Ser455) 11679 11527 4240 4485 p53(Phospho-Thr81) 23098 24763 22169 25038 p53(Phospho-Thr18) 19030 22638 14085 13643 >design <- cbind(mock.EGF=c(1,1,0,0,0,0,0,0),mock.no=c(0,0,1,1,0,0,0,0), WT.EGF=c(0,0,0,0,1,1,0,0),WT.no=c(0,0,0,0,0,0,1,1)) >fit <- lmFit(dat_mean, design) >cont.matrix <- makeContrasts(mock_LigvsNo=mock.EGF-mock.no,WT_LigvsNo=WT.EGF-WT.no,Lig_MockvsWT=mock.EGF-WT.EGF, No_MockvsWT=mock.no-WT.no,levels=design) >fit2 <- contrasts.fit(fit, cont.matrix) >fit2 <- eBayes(fit2) >results <- decideTests(fit2) >AA1<-topTable(fit2,coef=1,number=30,adjust="BH") >AA2 <- topTable(fit2,coef=2,number=30,adjust="BH") >AA3 <- topTable(fit2,coef=3,number=30,adjust="BH") >AA4 <- topTable(fit2,coef=4,number=30,adjust="BH")
Any comments/suggestions are highly acknowledged!
Dawn
While you're addressing Ryan's comment, also note that it looks like you are sending raw microarray data into limma.
You are going to want to normalize this data first. Minimally, you should take note that limma expects that the expression values be in log2 space.
Can you explain your problem in more detail and with examples?