Reduced purifying selection prevails over positive selection in human copy number variant evolution.

ABSTRACT: Copy number variation is a dominant contributor to genomic variation and may frequently underlie an individual's variable susceptibilities to disease. Here we question our previous proposition that copy number variants (CNVs) are often retained in the human population because of their adaptive benefit. We show that genic biases of CNVs are best explained, not by positive selection, but by reduced efficiency of selection in eliminating deleterious changes from the human population. Of four CNV data sets examined, three exhibit significant increases in protein evolutionary rates. These increases appear to be attributable to the frequent coincidence of CNVs with segmental duplications (SDs) that recombine infrequently. Furthermore, human orthologs of mouse genes, which, when disrupted, result

SUBMITTER: Nguyen DQ 

PROVIDER: S-EPMC2577867 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature