Population subdivision in westslope cutthroat trout (Oncorhynchus clarki lewisi) at the northern periphery of its range: evolutionary inferences and conservation implications
| Autor: | Eric B. Taylor, M. D. Stamford, J. S. Baxter |
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| Rok vydání: | 2003 |
| Předmět: |
Conservation of Natural Resources
Oncorhynchus Population Environment Genetic drift Gene Frequency Genetics Animals education Ecology Evolution Behavior and Systematics Salmonidae Isolation by distance education.field_of_study Principal Component Analysis biology British Columbia Geography Ecology Genetic Variation biology.organism_classification Biological Evolution Genetic divergence Trout Genetics Population Genetic distance Electrophoresis Polyacrylamide Gel Microsatellite Repeats |
| Zdroj: | Molecular ecology. 12(10) |
| ISSN: | 0962-1083 |
| Popis: | Westslope cutthroat trout (Oncorhynchus clarki lewisi, Salmonidae) are native to the upper Columbia, Missouri, and South Saskatchewan river drainages of western North America and are at the northern periphery of their range in southeastern British Columbia, Canada. We examined geographical variation in allele frequencies at eight microsatellite loci in 36 samples of westslope cutthroat trout from British Columbia to assess levels of population subdivision and to test the hypothesis that different habitat types (principally mainstem vs. above migration barrier habitats) would influence levels of genetic diversity, genetic divergence among populations, and attainment of equilibrium between gene flow and genetic drift. Across all samples, the mean number of alleles per locus was 3.9 and mean expected heterozygosity was 0.56. Population subdivision was extensive with an overall Fst (theta) of 0.32. Populations sampled above migration barriers had significantly fewer alleles, lower expected heterozygosity, but greater average pairwise Fst than populations sampled from mainstem localities. We found evidence for isolation-by-distance from a significant correlation between genetic distance and geographical distance (r = 0.31), but the pattern was much stronger (r = 0.51) when above barrier populations and a population that may have been involved in headwater exchanges were removed. By contrast, isolation-by-distance was not observed when only above barrier populations were tested among themselves. Our data support the maintenance of separate demographic management strategies for westslope cutthroat trout inhabiting different river systems and illustrate how differing habitat structure (e.g. presence of migration barriers) may influence patterns of biodiversity and gene flow-drift equilibrium. |
| Databáze: | OpenAIRE |
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