Dear Panagiotis, a quick question: Why do samples that are not part of any contrast affect the filtering? http://genomics-lab.fleming.gr/fleming/GPlab/run183/metaseqr_CtrlSal_vs_CtrlArs http://genomics-lab.fleming.gr/fleming/GPlab/run183/targets-run183.txt vs http://genomics-lab.fleming.gr/fleming/GPlab/run183/metaseqr_CtrlSal_vs_CtrlArs_only http://genomics-lab.fleming.gr/fleming/GPlab/run183/targets-run183.txt2 BW, Martin Dear Marina, pls. see the results at: http://genomics-lab.fleming.gr/fleming/GPlab/run179/metaseqr_CtrlSal_vs_TgSal/index.htmle Differential expression analysis for the contrasts CtrlSal versus TgSal using the Bioconductor package edgeR The final numbers of differentially expressed genes were (per contrast): for the contrast CtrlSal versus TgSal, 384 (2) statistically significant genes were found with a p-value (FDR or adjusted p-value) threshold of 0.05 and of these, 10 (2) were up-regulated, 2 (0) were down-regulated and 372 (0) were not differentially expressed according to an absolute fold change cutoff value of 1 in log2 scale. And at: http://genomics-lab.fleming.gr/fleming/GPlab/run183/metaseqr_CtrlArs_vs_TgArs/index.html Differential expression analysis for the contrasts CtrlArs versus TgArs using the Bioconductor package edgeR The final numbers of differentially expressed genes were (per contrast): for the contrast CtrlArs versus TgArs, 322 (2) statistically significant genes were found with a p-value (FDR or adjusted p-value) threshold of 0.05 and of these, 28 (1) were up-regulated, 8 (1) were down-regulated and 286 (0) were not differentially expressed according to an absolute fold change cutoff value of 1 in log2 scale. The other contrasts will follow, we can discuss this all later. Best wishes, Martin