Sequential adaptive introgression of the mitochondrial genome in Drosophila yakuba and Drosophila santomea
Article first published online: 26 FEB 2014
© 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Volume 23, Issue 5, pages 1124–1136, March 2014
How to Cite
Llopart, A., Herrig, D., Brud, E. and Stecklein, Z. (2014), Sequential adaptive introgression of the mitochondrial genome in Drosophila yakuba and Drosophila santomea. Molecular Ecology, 23: 1124–1136. doi: 10.1111/mec.12678
- Issue published online: 26 FEB 2014
- Article first published online: 26 FEB 2014
- Accepted manuscript online: 26 JAN 2014 07:17AM EST
- Manuscript Accepted: 15 JAN 2014
- Manuscript Revised: 9 JAN 2014
- Manuscript Received: 30 SEP 2013
- University of Iowa
- NIH Predoctoral Training Grant in Genetics. Grant Number: T32 GM008629014
- gene flow;
- positive selection;
- recurrent adaptation;
Interspecific hybridization provides the unique opportunity for species to tap into genetic variation present in a closely related species and potentially take advantage of beneficial alleles. It has become increasingly clear that when hybridization occurs, mitochondrial DNA (mtDNA) often crosses species boundaries, raising the possibility that it could serve as a recurrent target of natural selection and source of species' adaptations. Here we report the sequences of 46 complete mitochondrial genomes of Drosophila yakuba and Drosophila santomea, two sister species known to produce hybrids in nature (~3%). At least two independent events of mtDNA introgression are uncovered in this study, including an early invasion of the D. yakuba mitochondrial genome that fully replaced the D. santomea mtDNA native haplotypes and a more recent, ongoing event centred in the hybrid zone. Interestingly, this recent introgression event bears the signature of Darwinian natural selection, and the selective haplotype can be found at low frequency in Africa mainland populations of D. yakuba. We put forward the possibility that, because the effective population size of D. santomea is smaller than that of D. yakuba, the faster accumulation of mildly deleterious mutations associated with Muller's ratchet in the former species may have facilitated the replacement of the mutationally loaded mitochondrial genome of D. santomea by that of D. yakuba.