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Parallel introgression and selection on introduced alleles in a native species
Author(s) -
Bay Rachael A.,
Taylor Eric B.,
Schluter Dolph
Publication year - 2019
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.15097
Subject(s) - introgression , biology , rainbow trout , allele , oncorhynchus , evolutionary biology , trout , allopatric speciation , local adaptation , genetics , selection (genetic algorithm) , adaptation (eye) , balancing selection , population , gene , fishery , demography , artificial intelligence , neuroscience , sociology , fish <actinopterygii> , computer science
Abstract As humans cause the redistribution of species ranges, hybridization between previously allopatric species is on the rise. Such hybridization can have complex effects on overall fitness of native species as new allelic combinations are tested. Widespread species introductions provide a unique opportunity to study selection on introgressed alleles in independent, replicated populations. We examined selection on alleles that repeatedly introgressed from introduced rainbow trout ( Oncorhynchus mykiss ) into native westslope cutthroat trout ( Oncorhynchus clarkii lewisi ) populations in western Canada. We found that the degree of introgression of individual single nucleotide polymorphisms from the invasive species into the native is correlated between independent watersheds. A number of rainbow trout alleles have repeatedly swept to high frequency in native populations, suggesting parallel adaptive advantages. Using simulations, we estimated large selection coefficients up to 0.05 favoring several rainbow trout alleles in the native background. Although previous studies have found reduced hybrid fitness and genome‐wide resistance to introgression in westslope cutthroat trout, our results suggest that some introduced genomic regions are strongly favored by selection. Our study demonstrates the utility of replicated introductions as case studies for understanding parallel adaptation and the interactions between selection and introgression across the genome. We suggest that understanding this variation, including consideration of beneficial alleles, can inform management strategies for hybridizing species.