Demography or selection on linked cultural traits or genes? Investigating the driver of low mtDNA diversity in the sperm whale using complementary mitochondrial and nuclear genome analyses.

摘要: Mitochondrial DNA has been heavily utilized in phylogeography studies for several decades. However, underlying patterns of demography and may be misrepresented due to coalescence stochasticity, selection, variation mutation rates cultural hitchhiking (linkage genetic culturally-transmitted traits affecting fitness). Cultural suggested as an explanation low diversity species with strong social structures, counteracting even high mobility, abundance limited barriers dispersal. One such is the sperm whale, which shows very phylogeographic structure mtDNA despite a worldwide distribution large population. Here, we use analyses 175 globally distributed mitogenomes three nuclear genomes evaluate hypotheses population bottleneck/expansion vs. selective sweep or selection on mechanism contributing mitochondrial whales. In contrast control region (CR) data, mitogenome haplotypes are largely ocean-specific, only one 80 shared between Atlantic Pacific. Demographic suggest consistent global reduction size that ended approximately 125,000 years ago, correlated Eemian interglacial. Phylogeographic analysis suggests extant whales descend from maternal lineages endemic Pacific during period reduced have subsequently colonized times. Results highlight apparent impact past climate change, not sole processes responsible this highly species.