Dear mailing list, I am doing dual color hybridization using the last version of the miRNA microarrays from exiqon ("7th generation"). Applying the limma package, data are background corrected (normexp) and normalized (global loess), subsequently the 4 duplicates of each miRNA species are correlated (DupCor) and lmfit is performed. I used the following script, which works fine at least until exiqon version 11, since the 4 replicates are regularly distributed: # identify differentially expressed genes: design <- modelMatrix(targets, ref="Control") #show design design DupCor <- duplicateCorrelation(MA, design, ndups=4, spacing=2340) CorVal <- DupCor$consensus.correlation fit <- lmFit(MA, design, weights=MA$Weights, ndups=4, spacing=2340, correlation=DupCor$consensus.correlation) fit <- eBayes(fit) top = topTable(fit, adjust="BH", number=2340) write.table(top, file="toptable.txt", row.names=TRUE, col.names=TRUE, sep="\t") But the last version of the exiqon arrays have a different design, the spacing of the 4 replicates is not regular any more. 2 of the replicates are located within the same block, then, after a distance of 18 blocks, again 2 replicates in the same block. Block Column Row Name 11 7 8 hsa-miR-1/mmu-miR-1a-3p 11 7 18 hsa-miR-1/mmu-miR-1a-3p 29 7 8 hsa-miR-1/mmu-miR-1a-3p 29 7 18 hsa-miR-1/mmu-miR-1a-3p I tried to find a way to do it using the unique genenames for identifying the 4 replicates, but for these I only found the function average replicates (avereps), but it is not exactly what I want. Does anyone know how to perform DupCor using unique gene names?? Thanks a lot in advance, Christine -- output of sessionInfo(): R version 2.10.1 (2009-12-14) Copyright (C) 2009 The R Foundation for Statistical Computing ISBN 3-900051-07-0 R is free software and comes with ABSOLUTELY NO WARRANTY. You are welcome to redistribute it under certain conditions. Type 'license()' or 'licence()' for distribution details. Natural language support but running in an English locale R is a collaborative project with many contributors. Type 'contributors()' for more information and 'citation()' on how to cite R or R packages in publications. Type 'demo()' for some demos, 'help()' for on-line help, or 'help.start()' for an HTML browser interface to help. Type 'q()' to quit R. > workdir <-"P:/Area_Sanitaria/Area_Servizi/Ricerca/CARDIO_MOLECOLARE/Christine" > memory.limit(size = 2000) [1] 2000 > anname <- "Non-Diabetic.paired_trial_ave.rep" > > #Libraries > library(Biobase) Welcome to Bioconductor Vignettes contain introductory material. To view, type 'openVignette()'. To cite Bioconductor, see 'citation("Biobase")' and for packages 'citation(pkgname)'. > library(limma) > library(marray) > library(statmod) > library(arrayQuality) Loading required package: convert Loading required package: hexbin Loading required package: grid Loading required package: lattice Loading required package: gridBase Loading required package: RColorBrewer Warning message: replacing previous import ???summary??? when loading ???hexbin??? > library(annotate) Loading required package: AnnotationDbi -- Sent via the guest posting facility at bioconductor.org.