Abstract
Polymorphic species are useful models for investigating the evolutionary processes driving diversification. Such processes include colonization history as well as contemporary selection, gene flow, and genetic drift, which can vary between intraspecific morphs as a function of their distinct life histories. The interactive and relative influence of such evolutionary processes on morph differentiation critically informs morph-specific management decisions and our understanding of incipient speciation. We therefore investigated how geographic distance, environmental conditions, and colonization history interacted with morph migratory capacity in the highly polymorphic fish species, Arctic Charr (Salvelinus alpinus). Using an 87 k SNP chip we genetically characterized recently evolved anadromous, resident, and landlocked charr collected from 45 locations across a secondary contact zone of three charr glacial lineages in eastern Canada. A strong pattern of isolation by distance across all populations suggested geographic distance principally shaped genetic structure. Landlocked populations had lower genetic diversities and higher genetic differentiation than anadromous populations. However, effective population size was generally temporally stable in landlocked populations in comparison to anadromous populations. Genetic diversity positively correlated with latitude, potentially indicating southern anadromous populations' vulnerability to climate change and greater introgression between the Arctic and Atlantic glacial lineages in northern Labrador. Local adaptation was suggested by the observation of several environmental variables strongly associating with functionally relevant outlier genes including a region on chromosome AC21 potentially associated with anadromy. Our results demonstrate that gene flow, colonization history, and local adaptation uniquely interact to influence the genetic variation and evolutionary trajectory of populations.
| Original language | English |
|---|---|
| Pages (from-to) | 3025-3043 |
| Number of pages | 19 |
| Journal | Molecular Ecology |
| Volume | 32 |
| Issue number | 12 |
| Early online date | 3 Mar 2023 |
| DOIs | |
| Publication status | Published - Jun 2023 |
Bibliographical note
Funding Information:Thanks go to our editor and three anonymous reviewers whose suggestions greatly improved this study. We thank S. Avery, J. Callahan, S. Duffy, S. Hann, L. Pike, R. Solomon, A. Walsh, for assistance with sample collection and fieldwork. We are grateful to X. Dallaire and J.S. Moore for providing samples from Ungava, Bay (HAB) and to L. Bernatchez for his valuable comments on an earlier version of this manuscript. Thanks to Parks Canada for allowing us access to the Torngat Mountains National Park and the Nunatsiavut government for allowing us to collect samples from their lands. Thanks to A. Belay at Mount Sinai Hospital for her help with sequencing, A. Mesmer for help with genotyping, and S. Lehnert for insightful data analysis suggestions. We also thank the Institute for Biodiversity, Ecosystem Science, and Sustainability of the Department of Environment and Conservation of the Government of Labrador and Newfoundland for funding for this project; NSERC for the Strategic Grant STPGP 430198 and Discovery Grant awarded to DER, for the CGS‐D awarded to SJS; the Killam Trust for the Level 2 Izaak awarded to SJS; and the Government of Nova Scotia for the Graduate Scholarship awarded to SJS.
Publisher Copyright:
© 2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.
Data Availability Statement
A .ped file and corresponding .map file for all samples has been deposited in Dryad and is available at: https://doi.org/10.5061/dryad.wdbrv15sg. Additional metadata including weight, fork length, sex, maturity, and mtDNA D-loop haplotype (as assigned by Salisbury et al., 2019) measured for samples collected between 2010 and 2015 are available in Supporting Information Appendix S2Funding
Thanks go to our editor and three anonymous reviewers whose suggestions greatly improved this study. We thank S. Avery, J. Callahan, S. Duffy, S. Hann, L. Pike, R. Solomon, A. Walsh, for assistance with sample collection and fieldwork. We are grateful to X. Dallaire and J.S. Moore for providing samples from Ungava, Bay (HAB) and to L. Bernatchez for his valuable comments on an earlier version of this manuscript. Thanks to Parks Canada for allowing us access to the Torngat Mountains National Park and the Nunatsiavut government for allowing us to collect samples from their lands. Thanks to A. Belay at Mount Sinai Hospital for her help with sequencing, A. Mesmer for help with genotyping, and S. Lehnert for insightful data analysis suggestions. We also thank the Institute for Biodiversity, Ecosystem Science, and Sustainability of the Department of Environment and Conservation of the Government of Labrador and Newfoundland for funding for this project; NSERC for the Strategic Grant STPGP 430198 and Discovery Grant awarded to DER, for the CGS‐D awarded to SJS; the Killam Trust for the Level 2 Izaak awarded to SJS; and the Government of Nova Scotia for the Graduate Scholarship awarded to SJS.
UN SDGs
This output contributes to the following UN Sustainable Development Goals (SDGs)
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SDG 13 Climate Action
Keywords
- anadromy
- colonization history
- gene flow
- isolation by distance
- local adaptation
- morph
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