Genetic diversity within late-summer run and half-pounder steelhead (Oncorhynchus mykiss) in the Rogue River, Oregon.

Autor: Dayan, David I., Mazur, Steve, Green, Laura J., Wells, Andrew J., Johnson, Marc A., Van Dyke, Daniel J., Samarin, Peter A., Battleson, Ryan D., O'Malley, Kathleen G.
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Zdroj: Conservation Genetics; Feb2024, Vol. 25 Issue 1, p245-257, 13p
Abstrakt: Anadromous Oncorhynchus mykiss (steelhead) express diverse migratory behaviors and life-history strategies. Adult migration timing diversity within steelhead is often categorized into divergent early- and late-migration phenotypes. On the Rogue River in Oregon, adult steelhead return from the ocean during distinct early-summer, late-summer, and winter runs. Additionally, some juvenile steelhead briefly return to freshwater as "half pounders," before completing their oceanic growth phase and returning to freshwater again to spawn. Using markers from a Genotyping-in-Thousands by sequencing amplicon panel, we describe a genetic axis that discriminates between Rogue River steelhead that express early- vs. late-migration phenotypes. Then we examine whether late-summer run adults carry early- or late-migration associated alleles and assign half pounders as early or late migrators. Both late-summer run adults and half pounders bear highly heterozygous genotypes and recombined haplotypes at the greb1l–rock1 region on chromosome 28 associated with adult migration timing, suggestive of ongoing gene flow among individuals with early- and late-migration haplotypes. Our classification suggests that half pounders are a mixed assemblage of offspring from all three adult runs. We discuss the utility of markers within the greb1l–rock1 region to predict phenotypes and highlight the need to validate candidate gene-trait associations across lineages before applying them for management. Finally, we consider the implications of our results on the maintenance of life-history diversity within steelhead. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index