title: Evidence of recent signatures of selection during domestication in an Atlantic salmon population.
abstract: Selective breeding practices in Atlantic salmon aquaculture have been carried out intensively since the 1970s. Along with the phenotypic improvement of fish, we expect to observe genomic regions showing evidence of selection for traits related to growth and age at sexual maturation, as well as traits involved in the domestication process. This is mainly linked to the increase in the frequency of favourable alleles at loci that affect the traits of interest in the breeding population. In this study we searched for signatures of selection in the Cermaq Atlantic salmon broodstock, a Mowi strain, which was derived from wild Norwegian populations, and is now farmed in British Columbia, Canada. A 6.5K SNP array was used to genotype 202 fish from the Cermaq population, and the genotypes were compared with four wild populations from Norway. We used three methods based on FST values to detect signatures of selection. Forty four markers showing divergence in allele frequency were identified as outliers by the three detection methods, suggesting the presence of signatures of selection in the Cermaq population relative to their wild counterparts. Markers identified as outliers are associated with molecular functions that could be related to the selection for economically important traits (e.g., growth) as well as the domestication process (e.g., response to pathogens and environmental stressors). Of particular interest were three outlier markers that had been previously associated with grilsing (i.e., early sexual maturation) an undesirable trait, which has been heavily selected against in Atlantic salmon aquaculture. This study provides clear evidence of the presence of signatures of selection and domestication in a farmed Atlantic salmon population.
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada; The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, UK.
authors.forename: A P
authors.initials: AP
authors.lastname: Gutierrez
authors.affiliation: Faculty of Veterinary and Animal Sciences, University of Chile, Av. Santa Rosa, 11735, La Pintana, Santiago, Chile.
authors.forename: J M
authors.initials: JM
authors.lastname: Yáñez
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada. Electronic address: wdavidso@sfu.ca.
authors.forename: W S
authors.initials: WS
authors.lastname: Davidson
mesh_terms: D063147:Animal Distribution; D000818:Animals; D000835:Animals, Wild; D017756:Aquaculture; D001947:Breeding; D005819:Genetic Markers; D009664:Norway; D020641:Polymorphism, Single Nucleotide; D020317:Salmo salar / Q000235:genetics* / Q000502:physiology; D012641:Selection, Genetic
chemical_list: D005819:Genetic Markers
keywords: Atlantic salmon; Domestication; Grilsing; SNP array; Signatures of selection