Ancient chromosomal rearrangement associated with local adaptation of a postglacially colonized population of Atlantic Cod in the northwest Atlantic

Abstract Intraspecific diversity is central to the management and conservation of exploited species, yet knowledge of how this diversity is distributed and maintained in the genome of many marine species is lacking. Recent advances in genomic analyses allow for genome‐wide surveys of intraspecific d...

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Bibliographic Details
Published in:Molecular Ecology
Main Authors: Sinclair‐Waters, Marion, Bradbury, Ian R., Morris, Corey J., Lien, Sigbjørn, Kent, Matthew P., Bentzen, Paul
Other Authors: Natural Sciences and Engineering Research Council of Canada, Nova Scotia Graduate Scholarship, Genomics Research and Development Initiative
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2017
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Online Access:http://dx.doi.org/10.1111/mec.14442
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmec.14442
https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.14442
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Summary:Abstract Intraspecific diversity is central to the management and conservation of exploited species, yet knowledge of how this diversity is distributed and maintained in the genome of many marine species is lacking. Recent advances in genomic analyses allow for genome‐wide surveys of intraspecific diversity and offer new opportunities for exploring genomic patterns of divergence. Here, we analysed genome‐wide polymorphisms to measure genetic differentiation between an offshore migratory and a nonmigratory population and to define conservation units of Atlantic Cod ( Gadus morhua ) in coastal Labrador. A total of 141 individuals, collected from offshore sites and from a coastal site within Gilbert Bay, Labrador, were genotyped using an ~11k single nucleotide polymorphism array. Analyses of population structure revealed strong genetic differentiation between migratory offshore cod and nonmigratory Gilbert Bay cod. Genetic differentiation was elevated for loci within a chromosomal rearrangement found on linkage group 1 ( LG 1) that coincides with a previously found double inversion associated with migratory and nonmigratory ecotype divergence of cod in the northeast Atlantic. This inverted region includes several genes potentially associated with adaptation to differences in salinity and temperature, as well as influencing migratory behaviour. Our work provides evidence that a chromosomal rearrangement on LG 1 is associated with parallel patterns of divergence between migratory and nonmigratory ecotypes on both sides of the Atlantic Ocean.