Neutral and adaptive drivers of genomic change in introduced brook trout (Salvelinus fontinalis) populations revealed by pooled sequencing

• Published in: Ecology and evolution Vol. 12; no. 2; pp. e8584 - n/a
• Main Authors: Brookes, Brent, Jeon, Hyung‐Bae, Derry, Alison M., Post, John R., Rogers, Sean M., Humphries, Shelley, Fraser, Dylan J.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.02.2022; John Wiley and Sons Inc; Wiley
• Subjects: Adaptation; adaptive differentiation; Applied Ecology; Biodiversity; Colonization; Conservation Genetics; Differentiation; Economic impact; Environmental conditions; Environmental testing; Fish hatcheries; Freshwater lakes; Gene sequencing; Genetic analysis; Genetic diversity; Genetic load; Genetics; Genomes; Genomics; Introduced species; Invasive species; Lakes; Loci; Mountain lakes; National parks; neutral diversity; Nonnative species; Population Genetics; Populations; Pressure; Quantitative Genetics; Salvelinus fontinalis; Stochasticity; Success; Trout; whole‐genome sequencing; Canada; United States > US; adaptive differentiation; genetic diversity; whole‐genome sequencing; Salvelinus fontinalis; introduced species; neutral diversity
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.8584

Understanding the drivers of successful species invasions is important for conserving native biodiversity and for mitigating the economic impacts of introduced species. However, whole‐genome resolution investigations of the underlying contributions of neutral and adaptive genetic variation in successful introductions are rare. Increased propagule pressure should result in greater neutral genetic variation, while environmental differences should elicit selective pressures on introduced populations, leading to adaptive differentiation. We investigated neutral and adaptive variation among nine introduced brook trout (Salvelinus fontinalis) populations using whole‐genome pooled sequencing. The populations inhabit isolated alpine lakes in western Canada and descend from a common source, with an average of ~19 (range of 7–41) generations since introduction. We found some evidence of bottlenecks without recovery, no strong evidence of purifying selection, and little support that varying propagule pressure or differences in local environments shaped observed neutral genetic variation differences. Putative adaptive loci analysis revealed nonconvergent patterns of adaptive differentiation among lakes with minimal putatively adaptive loci (0.001%–0.15%) that did not correspond with tested environmental variables. Our results suggest that (i) introduction success is not always strongly influenced by genetic load; (ii) observed differentiation among introduced populations can be idiosyncratic, population‐specific, or stochastic; and (iii) conservatively, in some introduced species, colonization barriers may be overcome by support through one aspect of propagule pressure or benign environmental conditions. Understanding the drivers of successful species invasions is important for conserving native biodiversity and for mitigating the economic impacts of introduced species. We investigated neutral and adaptive variation among nine introduced high‐alpine brook trout (Salvelinus fontinalis) populations from a common source using whole‐genome pooled sequencing. We found some evidence of bottlenecks without recovery, no strong evidence of purifying selection, and little support that varying propagule pressure or differences in local environments shaped observed neutral genetic variation differences.