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Is structural variation necessary to create islands of divergence in moderate gene flow species? A case study in sockeye salmon
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  • Peter Euclide,
  • Wes Larson,
  • Yue Shi,
  • Kristen Gruenthal,
  • Kristen Christensen,
  • Jim Seeb,
  • Lisa Seeb
Peter Euclide
Purdue University

Corresponding Author:[email protected]

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Wes Larson
NOAA National Marine Fisheries Service
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Yue Shi
University of Alaska Fairbanks
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Kristen Gruenthal
State of Alaska Department of Fish and Game
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Kristen Christensen
University of Victoria
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Jim Seeb
University of Washington
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Lisa Seeb
University of Washington
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Local adaptation is often facilitated by loci clustered in relatively few regions of the genome, termed genomic islands of divergence. However, the mechanisms that create, mold, and maintain these islands are poorly understood. Here, we use sockeye salmon as a model species to investigate the mechanisms responsible for creating islands of divergence linked to adaptive variation. Previous research suggests that multiple islands are involved in adaptive radiation of sockeye salmon. However, these studies were based on low-density genomic methods that genotyped tens to thousands of loci, making it difficult to elucidate the mechanisms responsible for islands. We used whole genome resequencing to genotype millions of loci to investigate these mechanisms. We discovered 64 islands, 16 of which were shared between two isolated populations; these 16 islands were clustered in four genomic regions. Characterization of the shared regions suggested that three of four were likely created by chromosomal inversions, while the other was created by processes not involving structural variation. Additionally, all four regions were relatively small (< 600 kb), suggesting inversions and other low recombination regions do not have to span megabases to be important for adaptive divergence. In sum, our study demonstrates that heterogeneous selection can lead to a mosaic of islands created by different mechanisms within the same genome. Future studies should continue to investigate how gene flow, selection, and the architecture of genetic traits interact to influence the genomic landscape of adaptive divergence.
09 May 2023Submitted to Molecular Ecology
10 May 2023Submission Checks Completed
10 May 2023Assigned to Editor
10 May 2023Review(s) Completed, Editorial Evaluation Pending
12 May 2023Reviewer(s) Assigned
07 Jun 2023Editorial Decision: Revise Minor
01 Aug 20231st Revision Received
02 Aug 2023Submission Checks Completed
02 Aug 2023Assigned to Editor
02 Aug 2023Review(s) Completed, Editorial Evaluation Pending
14 Aug 2023Editorial Decision: Accept