Genomic islands of divergence and their consequences for the resolution of spatial structure in an exploited marine fish
Date
2013-04
Authors
Bradbury, Ian R.
Hubert, Sophie
Higgins, Brent
Bowman, Sharen
Borza, Tudor
Paterson, Ian G.
Snelgrove, Paul V. R.
Morris, Corey J.
Gregory, Robert S.
Hardie, David
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Abstract
As populations diverge, genomic regions associated with adaptation display elevated
differentiation. These genomic islands of adaptive divergence can inform conservation efforts in
exploited species, by refining the delineation of management units, and providing genomic tools for
more precise and effective population monitoring and the successful assignment of individuals and
products. We explored heterogeneity in genomic divergence and its impact on the resolution of
spatial population structure in exploited populations of Atlantic cod, Gadus morhua, using genome
wide expressed sequence derived single nucleotide polymorphisms in 466 individuals sampled across
the range. Outlier tests identified elevated divergence at 5.2% of SNPs, consistent with directional
selection in one-third of linkage groups. Genomic regions of elevated divergence ranged in size from
a single position to several cM. Structuring at neutral loci was associated with geographic
features, whereas outlier SNPs revealed genetic discontinuities in both the eastern and western
Atlantic. This fine-scale geographic differentiation enhanced assignment to region of origin, and
through the identification of adaptive diversity, fundamentally changes how these populations should
be conserved. This work demonstrates the utility of genome scans for adaptive divergence in the
delineation of stock structure, the traceability of individuals and products, and ultimately a role
for population genomics in fisheries conservation.
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Citation
Bradbury, Ian R., Sophie Hubert, Brent Higgins, Sharen Bowman, et al. 2013. "Genomic islands of divergence and their consequences for the resolution of spatial structure in
an exploited marine fish." Evolutionary Applications 6(3): 450-461.