Sequential adaptive introgression of the mitochondrial genome in Drosophila yakuba and Drosophila santomea

摘要: Interspecific hybridization provides the unique opportunity for species to tap into genetic variation present in a closely related and potentially take advantage of beneficial alleles. It has become increasingly clear that when occurs, mitochondrial DNA (mtDNA) often crosses boundaries, raising possibility it could serve as recurrent target natural selection source species' adaptations. Here we report sequences 46 complete genomes Drosophila yakuba santomea, two sister known produce hybrids nature (~3%). At least independent events mtDNA introgression are uncovered this study, including an early invasion D. yakuba genome fully replaced D. santomea native haplotypes more recent, ongoing event centred hybrid zone. Interestingly, recent bears signature Darwinian selection, selective haplotype can be found at low frequency Africa mainland populations D. yakuba. We put forward that, because effective population size is smaller than D. yakuba, faster accumulation mildly deleterious mutations associated with Muller's ratchet former may have facilitated replacement mutationally loaded by