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.
Highlights
Growth and age at sexual maturation are among the most important economic traits in Atlantic salmon (Salmo salar) aquaculture, with fish having been continuously selected for these traits since the beginning of selective breeding programs in Norway in the 1970s [1,2,3]
A total of 466 samples and 3,908 markers passed the Quality control (QC) and a genomewide association study (GWAS) was carried out to identify markers significantly associated with growth and late sexual maturation in Atlantic salmon
The use of molecular marker information could be a valuable tool to improve conventional broodstock selection programs by the identification of specific alleles that could be screened for and introduced into selected lines. This GWAS aimed to identify genomic regions associated with growth and sexual maturation
Summary
Growth and age at sexual maturation are among the most important economic traits in Atlantic salmon (Salmo salar) aquaculture, with fish having been continuously selected for these traits since the beginning of selective breeding programs in Norway in the 1970s [1,2,3]. Sexual maturation is considered a serious drawback for aquaculture as it retards growth for PLOS ONE | DOI:10.1371/journal.pone.0119730. The authors have reviewed the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors, http://www.PLOSone. The authors are pleased to be able to say that these associations do not contravene the PLOS ONE policies on this matter. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials. These associations do not preclude sharing data and materials, as detailed online in the journal’s guide for authors
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