Heritability estimation via molecular pedigree reconstruction in a wild fish population reveals substantial evolutionary potential for sea-age at maturity, but not size within age-classes

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Reed, Thomas E., Prodöhl, Paulo A., Bradley, Caroline, Gilbey, John, McGinnity, Philip, Primmer, Craig R., Bacon, Phil J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: NRC Research Press 2018
• Subjects: Salmonids; Population dynamics; Quantitative genetics; Bayesian; Evolvability; 38 adaptation; Management; Conservation genetics; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/10468/7876; https://doi.org/10.1139/cjfas-2018-0123

While evolutionary responses require heritable variation, estimates of heritability (h2) from wild fish populations remain rare. A 20-year molecular pedigree for a wild Scottish population of Atlantic salmon (Salmo salar) was used to investigate genetic contributions to (co)variation in two important, correlated, phenotypic traits: â sea ageâ (number of winters spent at sea prior to spawning) and size-at-maturity (body length just prior to spawning). Sea age was strongly heritable (h2 = 0.51) and size exhibited moderate heritability (h2 = 0.27). A very strong genetic correlation (rG = 0.96) between these traits implied the same functional loci must underpin variation in each. Indeed, body size within sea ages had much lower heritability that did not differ significantly from zero. Thus, within wild S. salar populations, temporal changes in sea age composition could reflect evolutionary responses, whereas rapid changes of body size within sea ages are more likely due to phenotypic plasticity. These inheritance patterns will influence the scope of evolutionary responses to factors such as harvest or climate change and, hence, have management implications for salmonid populations comprising a mix of sea ages. Si une variation héritable est nécessaire pour permettre des réactions évolutives, les estimations de l’héritabilité (h2) obtenues pour des populations sauvages demeurent rares. Un pedigree moléculaire de 20 ans pour une population sauvage écossaise de saumons atlantiques (Salmo salar) a été utilisé pour étudier les contributions génétiques à la (co)variation de deux caractères phénotypiques corrélés importants, à savoir « l’âge marin » (le nombre d’hivers passés en mer avant le frai) et la taille à la maturité (la longueur du corps juste avant le frai). L'âge marin est fortement héritable (h2 = 0,51) et la taille présente une héritabilité modérée (h2 = 0,27). Une corrélation génétique très forte (rG = 0,96) entre ces caractères indique que les mêmes sites fonctionnels doivent sous-tendre la variation des ...