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Selection at a Genomic Region of Major Effect is Responsible for Evolution of Complex Life Histories in Anadromous Steelhead

Feb 11, 2021


Disparity in the timing of biological events occurs across a variety of systems, yet the understanding of genetic basis underlying diverse phenologies remains limited. Variation in maturation timing occurs in steelhead trout, which has been associated with greb1L, an oestrogen target gene. Previous techniques that identified this gene only accounted for about 0.5–2.0% of the genome and solely investigated coastal populations, leaving uncertainty on the genetic basis of this trait and its prevalence across a larger geographic scale. This study clarifies the genetic bases for disparity in phenology observed in steelhead, determining an unanticipated trait association with premature versus mature arrival to spawning grounds and identifying multiple candidate genes potentially contributing to this variation from a single genomic region of major effect. This illustrates how dense genome mapping and detailed phenotypic characterization can clarify genotype to phenotype associations across geographic ranges of species.



Micheletti, S.J., J.E. Hess, J.S. Zendt, and S.R. Narum. 2018. Selection at a genomic region of major effect is responsible for evolution of complex life histories in anadromous steelhead. BMC Evolutionary Biology 18:140. Online at



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Journal Article