Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8304
Title: Mapping of quantitative trait loci for temporal growth and age at maturity in coho salmon: evidence for genotype-by-sex interactions
Author: Miyako Kodama, Jeffrey J. Hard, Kerry A. Naish
Publication Year: 2017
Journal: Marine Genomics
DOI: 10.1016/j.margen.2017.07.004

Characterizing the genetic architecture of life history traits, such the number of loci linked with the traits, the distribution of their effects and the degree of correlation helps understand the causal basis of phenotypic correlations, and contributes to an accurate prediction of adaptive evolutionary change. In a number of salmonid species, faster growing fish in a given cohort mature earlier than conspecifics, and growth performance during spring and fall are important in determining age at sexual maturity. The aim of this study was to investigate the causal mechanisms underlying a phenotypic correlation between age at sexual maturity and growth during these periods in coho salmon, by investigating the genetic architecture of age at sexual maturity and a suite of growth-related traits. We used a genome map based on 7415 non-duplicated RAD-sequenced tags to identify 37 Quantitative trait loci (QTL) linked to these traits in a study that spanned these decision periods. Several temporally expressed growth-related QTL mapped to the same position, suggesting that these regions affected growth across many months. We also found evidence for epistatic interactions between some growth traits, and that the effect of offspring sex on QTL expression differed. One genomic region was associated with age at sexual maturity and body length and weight measured during fall when maturation was initiated, indicating that the phenotypic correlation between these traits may be due to genetic pleiotropy or co-localization of genes. Our results provide insights into the genetic architecture underlying growth-related traits in coho salmon, and have implications for understanding the genetic and evolutionary basis of phenotypic correlations among important fitness-related traits.

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Theme: Recovery and rebuilding of marine and coastal species
Foci: Characterize the population biology of species, and develop and improve methods for predicting the status of populations.