Regulatory element copy number differences shape primate expression profiles.

Gene expression differences are shaped by selective pressures and contribute to phenotypic differences between species. We identified 964 copy number differences (CNDs) of conserved sequences across 3 primate species and examined their potential effects on gene expression profiles. Samples with copy number different genes had significantly different expression than samples with neutral copy number. Genes encoding regulatory molecules differed in copy number and were associated with significant expression differences. Additionally, we identified 127 CNDs which were processed pseudogenes and some of which were expressed. Furthermore, there were copy number different regulatory regions such as ultraconserved elements and long intergenic noncoding RNAs with the potential to affect expression. We postulate that CNDs of these conserved sequences fine-tune developmental pathways by altering the levels of RNA. Overall design: Gene expression patterns were compared between human, chimpanzee and rhesus macaque lymphoblastoid cell lines using RNA-Seq. Samples from 6 individuals of each species were used. The 6 human samples were previously published as a part of GEO record GSE19480 (samples GSM485426, GSM485428, GSM485468, GSM485410, GSM485413 and GSM485414). The 6 chimpanzee and 6 rhesus macaquesamples are included in the current record (GSE38572).