title: Genome-wide association study (GWAS) for growth rate and age at sexual maturation in Atlantic salmon (Salmo salar).
abstract: Early sexual maturation is considered a serious drawback for Atlantic salmon aquaculture as it retards growth, increases production times and affects flesh quality. Although both growth and sexual maturation are thought to be complex processes controlled by several genetic and environmental factors, selection for these traits has been continuously accomplished since the beginning of Atlantic salmon selective breeding programs. In this genome-wide association study (GWAS) we used a 6.5K single-nucleotide polymorphism (SNP) array to genotype ∼ 480 individuals from the Cermaq Canada broodstock program and search for SNPs associated with growth and age at sexual maturation. Using a mixed model approach we identified markers showing a significant association with growth, grilsing (early sexual maturation) and late sexual maturation. The most significant associations were found for grilsing, with markers located in Ssa10, Ssa02, Ssa13, Ssa25 and Ssa12, and for late maturation with markers located in Ssa28, Ssa01 and Ssa21. A lower level of association was detected with growth on Ssa13. Candidate genes, which were linked to these genetic markers, were identified and some of them show a direct relationship with developmental processes, especially for those in association with sexual maturation. However, the relatively low power to detect genetic markers associated with growth (days to 5 kg) in this GWAS indicates the need to use a higher density SNP array in order to overcome the low levels of linkage disequilibrium observed in Atlantic salmon before the information can be incorporated into a selective breeding program.
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Alejandro P
authors.initials: AP
authors.lastname: Gutierrez
authors.affiliation: Faculty of Veterinary and Animal Sciences, University of Chile, Santiago, Chile.
authors.forename: José M
authors.initials: JM
authors.lastname: Yáñez
authors.affiliation: Cermaq Canada, Campbell River, British Columbia, Canada.
authors.forename: Steve
authors.initials: S
authors.lastname: Fukui
authors.affiliation: TRI-GEN Fish Improvement Ltd., Agassiz, British Columbia, Canada.
authors.forename: Bruce
authors.initials: B
authors.lastname: Swift
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: William S
authors.initials: WS
authors.lastname: Davidson
mesh_terms: D000818:Animals; D017756:Aquaculture; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics; D005260:Female; D029941:Fish Proteins / Q000235:genetics; D055106:Genome-Wide Association Study; D005838:Genotype; D015810:Linkage Disequilibrium; D008297:Male; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D020317:Salmo salar / Q000235:genetics*; D012741:Sexual Maturation / Q000235:genetics*
chemical_list: D029941:Fish Proteins