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Outlier loci highlight the direction of introgression in oaks
Author(s) -
Guichoux E.,
GarnierGéré P.,
Lagache L.,
Lang T.,
Boury C.,
Petit R. J.
Publication year - 2013
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12125
Subject(s) - biology , introgression , quercus petraea , interspecific competition , evolutionary biology , sympatric speciation , gene flow , coalescent theory , selection (genetic algorithm) , ecology , genetics , genetic variation , phylogenetic tree , gene , artificial intelligence , computer science
Loci considered to be under selection are generally avoided in attempts to infer past demographic processes as they do not fit neutral model assumptions. However, opportunities to better reconstruct some aspects of past demography might thus be missed. Here we examined genetic differentiation between two sympatric E uropean oak species with contrasting ecological dynamics ( Q uercus robur and Q uercus petraea ) with both outlier (i.e. loci possibly affected by divergent selection between species or by hitchhiking effects with genomic regions under selection) and nonoutlier loci. We sampled 855 individuals in six mixed forests in F rance and genotyped them with a set of 262 SNP s enriched with markers showing high interspecific differentiation, resulting in accurate species delimitation. We identified between 13 and 74 interspecific outlier loci, depending on the coalescent simulation models and parameters used. Greater genetic diversity was predicted in Q . petraea (a late‐successional species) than in Q . robur (an early successional species) as introgression should theoretically occur predominantly from the resident species to the invading species. Remarkably, this prediction was verified with outlier loci but not with nonoutlier loci. We suggest that the lower effective interspecific gene flow at loci showing high interspecific divergence has better preserved the signal of past asymmetric introgression towards Q . petraea caused by the species' contrasting dynamics. Using markers under selection to reconstruct past demographic processes could therefore have broader potential than generally recognized.