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Genomic dynamics of brown trout (Salmo trutta) populations released to a novel environment
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  • Sara Kurland,
  • Nima Rafati,
  • Nils Ryman,
  • Linda Laikre
Sara Kurland
Stockholms University Department of Zoology

Corresponding Author:[email protected]

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Nima Rafati
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Nils Ryman
Stockholm University
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Linda Laikre
Stockholm University
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Understanding the consequences of human induced translocations on natural populations requires genetic monitoring. Salmonid fishes represent a group of species experiencing several such large-scale perturbations expected to affect microevolutionary processes. Here, two genetically separate brown trout populations with divergent life history traits are studied following their release into waters previously void of trout. We use a pooled sequencing approach to explore the genomic characteristics of the released stocks and of populations established in the wild in two lakes down-stream of the release site 30 years (4-5 generations) later. While most of the differences (FST=0.16) between the released stocks can be attributed to drift, we identify putatively adaptive differences between them in genes involved in immunity, hearing, skin and muscle texture. Higher levels of genome-wide diversity in established populations compared to released stocks suggest extensive hybridization between stocks. However, released stocks are unequally represented in the established populations, with one stock mainly contributing to the lake closest to the release site, and the other dominating the lake further downstream. We also identify genomic regions putatively under directional selection in the new environment, where genes from one of the released populations, governing metabolism, appear advantageous. Our results demonstrate that hybridization, establishment, and adaptation can be rapid after release into novel environments. We show that such ongoing processes, important for conservation and management, are possible to monitor over contemporary time scales even for a species with relatively small local effective population sizes and a large, complex genome.
30 Mar 2022Submission Checks Completed
30 Mar 2022Assigned to Editor
01 Apr 2022Review(s) Completed, Editorial Evaluation Pending
05 Apr 2022Editorial Decision: Revise Minor
04 Jun 20221st Revision Received
04 Jun 2022Submission Checks Completed
04 Jun 2022Assigned to Editor
04 Jun 2022Review(s) Completed, Editorial Evaluation Pending
04 Jun 2022Editorial Decision: Accept