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GENOMIC REGIONS WITH A HISTORY OF DIVERGENT SELECTION AFFECT FITNESS OF HYBRIDS BETWEEN TWO BUTTERFLY SPECIES
Author(s) -
Gompert Zachariah,
Lucas Lauren K.,
Nice Chris C.,
Fordyce James A.,
Forister Matthew L.,
Buerkle C. Alex
Publication year - 2012
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2012.01587.x
Subject(s) - biology , reproductive isolation , introgression , evolutionary biology , locus (genetics) , ecological speciation , genetics , population , incipient speciation , genetic diversity , hybrid , gene flow , genetic variation , gene , demography , botany , sociology
Speciation is the process by which reproductively isolated lineages arise, and is one of the fundamental means by which the diversity of life increases. Whereas numerous studies have documented an association between ecological divergence and reproductive isolation, relatively little is known about the role of natural selection in genome divergence during the process of speciation. Here, we use genome‐wide DNA sequences and Bayesian models to test the hypothesis that loci under divergent selection between two butterfly species ( Lycaeides idas and L. melissa ) also affect fitness in an admixed population. Locus‐specific measures of genetic differentiation between L. idas and L. melissa and genomic introgression in hybrids varied across the genome. The most differentiated genetic regions were characterized by elevated L. idas ancestry in the admixed population, which occurs in L. idas ‐like habitat, consistent with the hypothesis that local adaptation contributes to speciation. Moreover, locus‐specific measures of genetic differentiation (a metric of divergent selection) were positively associated with extreme genomic introgression (a metric of hybrid fitness). Interestingly, concordance of differentiation and introgression was only partial. We discuss multiple, complementary explanations for this partial concordance.