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Willis S, Coykendall DK, Campbell MR, Narum S. Contrasting patterns of sequence variation in steelhead populations reflect distinct evolutionary processes. Evol Appl 2024; 17:e13623. [PMID: 38283605 PMCID: PMC10810252 DOI: 10.1111/eva.13623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/24/2023] [Accepted: 11/10/2023] [Indexed: 01/30/2024] Open
Abstract
Multiple evolutionary processes influence genome-wide allele frequencies and quantifying effects of genetic drift, and multiple forms of selection remain challenging in natural populations. Here, we investigate variation at major effect loci in contrast to patterns of neutral drift across a wide collection of steelhead (Oncorhynchus mykiss) populations that have declined in abundance due to anthropogenic impacts. Whole-genome resequencing of 74 populations of steelhead revealed genome-wide patterns (~8 million SNPs) consistent with expected neutral population structure. However, allelic variation at major effect loci associated with adult migration timing (chromosome 28: GREB1L/ROCK1) and age at maturity (chromosome 25: SIX6) reflected how selection has acted on phenotypic variation in contrast with neutral structure. Variation at major effect loci was influenced by evolutionary processes with differing signals between the strongly divergent Coastal and Inland lineages, while allele frequencies within and among populations within the Inland lineage have been driven by local natural selection as well as recent anthropogenic influences. Recent anthropogenic effects appeared to have influenced the frequency of major effect alleles including artificial selection for specific traits in hatchery stocks with subsequent gene flow into natural populations. Selection from environmental factors at various scales has also likely influenced variation for major effect alleles. These results reveal evolutionary mechanisms that influence allele frequencies at major effect loci that are critical for conservation of phenotypic traits and life history variation of this protected species.
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Affiliation(s)
- Stuart Willis
- Hagerman Genetics LabColumbia River Inter‐Tribal Fish CommissionHagermanIdahoUSA
| | | | | | - Shawn Narum
- Hagerman Genetics LabColumbia River Inter‐Tribal Fish CommissionHagermanIdahoUSA
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Horn RL, Narum SR. Going the distance to test local adaptation in Coho salmon. Mol Ecol 2023; 32:539-541. [PMID: 36453162 DOI: 10.1111/mec.16792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/08/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022]
Abstract
The mechanisms underlying local adaptation, where populations evolve traits that confer advantages to the local environment, is a central topic for understanding evolution in natural systems. Conservation goals for species at risk often include defining population boundaries by identifying gene diversity, genetic differentiation, and adaptation to local environments. In this issue of Molecular Ecology, Rougemont et al. (2022) combine genome-wide SNP data with an extensive set of landscape variables to study the genomic mechanisms of local adaptation in the entire North American range of Coho salmon (Oncorhynchus kisutch), representing one of the largest studies of its kind. Migration distance, defined as the distance adult Coho salmon migrate from the ocean to their freshwater spawning ground, was found to be the primary factor driving local adaptation in this species. With climatic changes altering flow regimes and therefore the success of Coho salmon to return to spawning grounds, understanding environmental drivers and the genomic basis for migration is essential in the conservation of anadromous salmonids.
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Affiliation(s)
- Rebekah L Horn
- Columbia River Inter-Tribal Fish Commission, Hagerman, Idaho, USA
| | - Shawn R Narum
- Columbia River Inter-Tribal Fish Commission, Hagerman, Idaho, USA
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Collins EE, Romero N, Zendt JS, Narum SR. Whole-Genome Resequencing to Evaluate Life History Variation in Anadromous Migration of Oncorhynchus mykiss. Front Genet 2022; 13:795850. [PMID: 35368705 PMCID: PMC8964970 DOI: 10.3389/fgene.2022.795850] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/24/2022] [Indexed: 12/04/2022] Open
Abstract
Anadromous fish experience physiological modifications necessary to migrate between vastly different freshwater and marine environments, but some species such as Oncorhynchus mykiss demonstrate variation in life history strategies with some individuals remaining exclusively resident in freshwater, whereas others undergo anadromous migration. Because there is limited understanding of genes involved in this life history variation across populations of this species, we evaluated the genomic difference between known anadromous (n = 39) and resident (n = 78) Oncorhynchus mykiss collected from the Klickitat River, WA, USA, with whole-genome resequencing methods. Sequencing of these collections yielded 5.64 million single-nucleotide polymorphisms that were tested for significant differences between resident and anadromous groups along with previously identified candidate gene regions. Although a few regions of the genome were marginally significant, there was one region on chromosome Omy12 that provided the most consistent signal of association with anadromy near two annotated genes in the reference assembly: COP9 signalosome complex subunit 6 (CSN6) and NACHT, LRR, and PYD domain–containing protein 3 (NLRP3). Previously identified candidate genes for anadromy within the inversion region of chromosome Omy05 in coastal steelhead and rainbow trout were not informative for this population as shown in previous studies. Results indicate that the significant region on chromosome Omy12 may represent a minor effect gene for male anadromy and suggests that this life history variation in Oncorhynchus mykiss is more strongly driven by other mechanisms related to environmental rearing such as epigenetic modification, gene expression, and phenotypic plasticity. Further studies into regulatory mechanisms of this trait are needed to understand drivers of anadromy in populations of this protected species.
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Affiliation(s)
- Erin E. Collins
- Hagerman Genetics Laboratory, Columbia River Inter-Tribal Fish Commission, Hagerman, ID, United States
- *Correspondence: Erin E. Collins,
| | - Nicolas Romero
- Yakama Nation Fisheries, Yakima/Klickitat Fisheries Project, Klickitat, WA, United States
| | - Joseph S. Zendt
- Yakama Nation Fisheries, Yakima/Klickitat Fisheries Project, Klickitat, WA, United States
| | - Shawn R. Narum
- Hagerman Genetics Laboratory, Columbia River Inter-Tribal Fish Commission, Hagerman, ID, United States
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Brookes B, Jeon H, Derry AM, Post JR, Rogers SM, Humphries S, Fraser DJ. Neutral and adaptive drivers of genomic change in introduced brook trout ( Salvelinus fontinalis) populations revealed by pooled sequencing. Ecol Evol 2022; 12:e8584. [PMID: 35154655 PMCID: PMC8820109 DOI: 10.1002/ece3.8584] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 01/07/2022] [Indexed: 12/22/2022] Open
Abstract
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.
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Affiliation(s)
- Brent Brookes
- Department of BiologyConcordia UniversityMontréalQCCanada
| | - Hyung‐Bae Jeon
- Department of BiologyConcordia UniversityMontréalQCCanada
| | - Alison M. Derry
- Département des sciences biologiquesUniversité du Québec à MontréalMontréalQCCanada
| | - John R. Post
- Department of BiologyUniversity of CalgaryCalgaryABCanada
| | - Sean M. Rogers
- Department of BiologyUniversity of CalgaryCalgaryABCanada
| | - Shelley Humphries
- Parks CanadaNatural Resource Management BranchRadium Hot SpringsBCCanada
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Schweizer RM, Saarman N, Ramstad KM, Forester BR, Kelley JL, Hand BK, Malison RL, Ackiss AS, Watsa M, Nelson TC, Beja-Pereira A, Waples RS, Funk WC, Luikart G. Big Data in Conservation Genomics: Boosting Skills, Hedging Bets, and Staying Current in the Field. J Hered 2021; 112:313-327. [PMID: 33860294 DOI: 10.1093/jhered/esab019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/13/2021] [Indexed: 02/07/2023] Open
Abstract
A current challenge in the fields of evolutionary, ecological, and conservation genomics is balancing production of large-scale datasets with additional training often required to handle such datasets. Thus, there is an increasing need for conservation geneticists to continually learn and train to stay up-to-date through avenues such as symposia, meetings, and workshops. The ConGen meeting is a near-annual workshop that strives to guide participants in understanding population genetics principles, study design, data processing, analysis, interpretation, and applications to real-world conservation issues. Each year of ConGen gathers a diverse set of instructors, students, and resulting lectures, hands-on sessions, and discussions. Here, we summarize key lessons learned from the 2019 meeting and more recent updates to the field with a focus on big data in conservation genomics. First, we highlight classical and contemporary issues in study design that are especially relevant to working with big datasets, including the intricacies of data filtering. We next emphasize the importance of building analytical skills and simulating data, and how these skills have applications within and outside of conservation genetics careers. We also highlight recent technological advances and novel applications to conservation of wild populations. Finally, we provide data and recommendations to support ongoing efforts by ConGen organizers and instructors-and beyond-to increase participation of underrepresented minorities in conservation and eco-evolutionary sciences. The future success of conservation genetics requires both continual training in handling big data and a diverse group of people and approaches to tackle key issues, including the global biodiversity-loss crisis.
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Affiliation(s)
- Rena M Schweizer
- Division of Biological Sciences, University of Montana, Missoula, MT
| | - Norah Saarman
- Department of Biology, Utah State University, Logan, UT
| | - Kristina M Ramstad
- Department of Biology and Geology, University of South Carolina Aiken, Aiken, SC
| | | | - Joanna L Kelley
- School of Biological Sciences, Washington State University, Pullman, WA
| | - Brian K Hand
- Division of Biological Sciences, University of Montana, Missoula, MT.,Flathead Lake Biological Station, University of Montana, Polson, MT
| | - Rachel L Malison
- Flathead Lake Biological Station, University of Montana, Polson, MT
| | - Amanda S Ackiss
- Wisconsin Cooperative Fishery Research Unit, University of Wisconsin Stevens Point, Stevens Point, WI
| | | | | | - Albano Beja-Pereira
- Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO-UP), InBIO, Universidade do Porto, Vairão, Portugal.,DGAOT, Faculty of Sciences, University of Porto, Porto, Portugal.,Sustainable Agrifood Production Research Centre (GreenUPorto), Faculty of Sciences, University of Porto, Porto, Portugal
| | - Robin S Waples
- Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA
| | - W Chris Funk
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO
| | - Gordon Luikart
- Division of Biological Sciences, University of Montana, Missoula, MT.,Flathead Lake Biological Station, University of Montana, Polson, MT
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Chen Z, Narum SR. Whole genome resequencing reveals genomic regions associated with thermal adaptation in redband trout. Mol Ecol 2020; 30:162-174. [PMID: 33135227 DOI: 10.1111/mec.15717] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022]
Abstract
Adaptation to local environments involves evolution of ecologically important traits and underlying physiological processes. Here, we used low coverage whole-genome resequencing (lcWGR) on individuals to identify genome regions involved in thermal adaptation in wild redband trout Oncorhynchus mykiss gairdneri, a subspecies of rainbow trout that inhabits ecosystems ranging from cold montane forests to high elevation deserts. This study includes allele frequency-based analyses for selective sweeps among populations, followed by multiple association tests for specific sets of phenotypes measured under thermal stress (acute and chronic survival/mortality; high or low cardiac performance groups). Depending on the groups in each set of analyses, sequencing reads covered 43%-75% of the genome at ≥15× and each analysis included millions of SNPs across the genome. In tests for selective sweeps among populations, a total of six chromosomal regions were significant. The further association tests for specific phenotypes revealed that the region on chromosome 4 was consistently the most significant and contains the cerk gene (ceramide kinase). This study provides insight into a potential genetic mechanism of local thermal adaptation and suggests cerk may be an important candidate gene. However, further validation of this cerk gene is necessary to determine if the association with cardiac performance results in a functional role to influence thermal performance when exposed to high water temperatures and hypoxic conditions.
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Affiliation(s)
- Zhongqi Chen
- Aquaculture Research Institute, University of Idaho, Hagerman, ID, USA
| | - Shawn R Narum
- Aquaculture Research Institute, University of Idaho, Hagerman, ID, USA.,Columbia River Inter-Tribal Fish Commission, Hagerman, ID, USA
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