RT Journal Article
SR Electronic
T1 Similar efficacies of selection shape mitochondrial and nuclear genes in <em>Drosophila melanogaster</em> and <em>Homo sapiens</em>
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 010355
DO 10.1101/010355
A1 Brandon S. Cooper
A1 Chad R. Burrus
A1 Chao Ji
A1 Matthew W. Hahn
A1 Kristi L. Montooth
YR 2015
UL http://biorxiv.org/content/early/2015/06/05/010355.abstract
AB Deleterious mutations contribute to polymorphism even when selection effectively prevents their fixation. The efficacy of selection in removing deleterious mitochondrial mutations from populations depends on the effective population size (Ne) of the mtDNA, and the degree to which a lack of recombination magnifies the effects of linked selection. Using complete mitochondrial genomes from Drosophila melanogaster and nuclear data available from the same samples, we re-examine the hypothesis that non-recombining animal mtDNA harbor an excess of deleterious polymorphisms relative to the nuclear genome. We find no evidence of recombination in the mitochondrial genome, and the much-reduced level of mitochondrial synonymous polymorphism relative to nuclear genes is consistent with a reduction in Ne. Nevertheless, we find that the neutrality index (NI), a measure of the excess of nonsynonymous polymorphism relative to the neutral expectation, is not significantly different between mitochondrial and nuclear loci. Reanalysis of published data from Homo sapiens reveals the same lack of a difference between the two genomes, though small samples in previous studies had suggested a strong difference in both species. Thus, despite a smaller Ne, mitochondrial loci of both flies and humans appear to experience similar efficacies of selection as do loci in the recombining nuclear genome.