I know there are lots of discussion about this. But all sorts of distributions were mention regarding both differential expression gene and non-differential expression gene. I have not found anything conclusive. Maybe this is still an unsettled issue. But here is what I thought:
I have been under the impression that not differentially expressed gene would follow negative binomial distribution due to biological / technical variation. In the cancer sample pool, over / under expressed genes would follow negative bibomial distribution as well maybe with even larger variance. In the cancer / normal mixed sample pool, differentially expressed gene may follow bimodal distribution representing normal expression and tumor expression respectively. Do I understand these right?