Gene-flow in a mosaic hybrid zone: is local introgression adaptive?

Détails

ID Serval
serval:BIB_682A18A3A525
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Gene-flow in a mosaic hybrid zone: is local introgression adaptive?
Périodique
Genetics
Auteur(s)
Fraïsse C., Roux C., Welch J.J., Bierne N.
ISSN
1943-2631 (Electronic)
ISSN-L
0016-6731
Statut éditorial
Publié
Date de publication
2014
Volume
197
Numéro
3
Pages
939-951
Langue
anglais
Résumé
Genome-wide scans of genetic differentiation between hybridizing taxa can identify genome regions with unusual rates of introgression. Regions of high differentiation might represent barriers to gene flow, while regions of low differentiation might indicate adaptive introgression-the spread of selectively beneficial alleles between reproductively isolated genetic backgrounds. Here we conduct a scan for unusual patterns of differentiation in a mosaic hybrid zone between two mussel species, Mytilus edulis and M. galloprovincialis. One outlying locus, mac-1, showed a characteristic footprint of local introgression, with abnormally high frequency of edulis-derived alleles in a patch of M. galloprovincialis enclosed within the mosaic zone, but low frequencies outside of the zone. Further analysis of DNA sequences showed that almost all of the edulis allelic diversity had introgressed into the M. galloprovincialis background in this patch. We then used a variety of approaches to test the hypothesis that there had been adaptive introgression at mac-1. Simulations and model fitting with maximum-likelihood and approximate Bayesian computation approaches suggested that adaptive introgression could generate a "soft sweep," which was qualitatively consistent with our data. Although the migration rate required was high, it was compatible with the functioning of an effective barrier to gene flow as revealed by demographic inferences. As such, adaptive introgression could explain both the reduced intraspecific differentiation around mac-1 and the high diversity of introgressed alleles, although a localized change in barrier strength may also be invoked. Together, our results emphasize the need to account for the complex history of secondary contacts in interpreting outlier loci.
Mots-clé
Mytilus, approximate Bayesian computation, maximum likelihood, outlier loci, soft sweep
Pubmed
Web of science
Open Access
Oui
Création de la notice
21/08/2014 8:33
Dernière modification de la notice
20/08/2019 14:23
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