Hi, I am using limma. Here is a error I met SubM is a 19k by 6 matrix > design [1] 1 1 1 -1 -1 -1 > PMAfit<-lmFit(subM,design,ndups=2,spacing=1,correlation=mycor$cor,weig hts=NULL) > PMAfit<-ebayes(PMAfit) > topT<-topTable(PMAfit,number=200,sort.by="P",genelist=genelist,adjust= "fdr") Error in array(x, c(length(x), 1), if (!is.null(names(x))) list(names(x), : attempt to set an attribute on NULL Thanks