Can we continue to neglect genomic variation in introgression rates when inferring the history of speciation? A case study in a Mytilus hybrid zone.

Détails

ID Serval
serval:BIB_5509947B5594
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Can we continue to neglect genomic variation in introgression rates when inferring the history of speciation? A case study in a Mytilus hybrid zone.
Périodique
Journal of Evolutionary Biology
Auteur⸱e⸱s
Roux C., Fraïsse C., Castric V., Vekemans X., Pogson G.H., Bierne N.
ISSN
1420-9101 (Electronic)
ISSN-L
1010-061X
Statut éditorial
Publié
Date de publication
2014
Volume
27
Numéro
8
Pages
1662-1675
Langue
anglais
Résumé
The use of molecular data to reconstruct the history of divergence and gene flow between populations of closely related taxa represents a challenging problem. It has been proposed that the long-standing debate about the geography of speciation can be resolved by comparing the likelihoods of a model of isolation with migration and a model of secondary contact. However, data are commonly only fit to a model of isolation with migration and rarely tested against the secondary contact alternative. Furthermore, most demographic inference methods have neglected variation in introgression rates and assume that the gene flow parameter (Nm) is similar among loci. Here, we show that neglecting this source of variation can give misleading results. We analysed DNA sequences sampled from populations of the marine mussels, Mytilus edulis and M. galloprovincialis, across a well-studied mosaic hybrid zone in Europe and evaluated various scenarios of speciation, with or without variation in introgression rates, using an Approximate Bayesian Computation (ABC) approach. Models with heterogeneous gene flow across loci always outperformed models assuming equal migration rates irrespective of the history of gene flow being considered. By incorporating this heterogeneity, the best-supported scenario was a long period of allopatric isolation during the first three-quarters of the time since divergence followed by secondary contact and introgression during the last quarter. By contrast, constraining migration to be homogeneous failed to discriminate among any of the different models of gene flow tested. Our simulations thus provide statistical support for the secondary contact scenario in the European Mytilus hybrid zone that the standard coalescent approach failed to confirm. Our results demonstrate that genomic variation in introgression rates can have profound impacts on the biological conclusions drawn from inference methods and needs to be incorporated in future studies.
Mots-clé
introgression, molecular evolution, natural selection, population genetics, simulation, speciation
Pubmed
Web of science
Création de la notice
28/08/2014 10:36
Dernière modification de la notice
20/08/2019 14:09
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