Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
Faroe Marine Research Institute, Tórshavn, Faroe Islands.
Mol Ecol. 2024 Aug;33(16):e17465. doi: 10.1111/mec.17465. Epub 2024 Jul 12.
The ecological role of heritable phenotypic variation in free-living populations remains largely unknown. Knowledge of the genetic basis of functional ecological processes can link genomic and phenotypic diversity, providing insight into polymorphism evolution and how populations respond to environmental changes. By quantifying the marine diet of Atlantic salmon, we assessed how foraging behaviour changes along the ontogeny, and in relation to genetic variation in two loci with major effects on age at maturity (six6 and vgll3). We used a two-component, zero-inflated negative binomial model to simultaneously quantify foraging frequency and foraging outcome, separately for fish and crustaceans diets. We found that older salmon forage for both prey types more actively (as evidenced by increased foraging frequency), but with a decreased efficiency (as evidenced by fewer prey in the diet), suggesting an age-dependent shift in foraging dynamics. The vgll3 locus was linked to age-dependent changes in foraging behaviour: Younger salmon with vgll3 (the genotype associated with late maturation) tended to forage crustaceans more often than those with vgll3 (the genotype associated with early maturation), whereas the pattern was reversed in older salmon. Vgll3 genotype was also linked to a marginal increase in fish acquisition, especially in younger salmon, while six6 was not a factor explaining the diet variation. Our results suggest a functional role for marine feeding behaviour linking genomic diversity at vgll3 with age at maturity among salmon, with potential age-dependent trade-offs maintaining the genetic variation. A shared genetic basis between dietary ecology and age at maturity likely subjects Atlantic salmon populations to evolution induced by bottom-up changes in marine productivity.
遗传表型变异在自由生活种群中的生态作用在很大程度上仍然未知。对功能生态过程遗传基础的了解可以将基因组和表型多样性联系起来，深入了解多态性进化以及种群如何应对环境变化。通过量化大西洋鲑的海洋饮食，我们评估了觅食行为如何随个体发育而变化，以及在两个对成熟年龄有主要影响的基因座（six6 和 vgll3）的遗传变异方面如何变化。我们使用两部分、零膨胀负二项式模型来同时量化觅食频率和觅食结果，分别针对鱼类和甲壳类动物的饮食。我们发现，年龄较大的鲑鱼更积极地觅食两种猎物类型（这一点可以通过增加觅食频率来证明），但效率却降低了（这一点可以从饮食中的猎物减少来证明），这表明觅食动态随年龄的变化而变化。vgll3 基因座与觅食行为的年龄依赖性变化有关：具有 vgll3（与晚期成熟相关的基因型）的年轻鲑鱼比具有 vgll3（与早期成熟相关的基因型）的鲑鱼更倾向于捕食甲壳类动物，而在年龄较大的鲑鱼中则相反。vgll3 基因型还与鱼类获取量的边际增加有关，尤其是在年轻的鲑鱼中，而 six6 不是解释饮食变化的因素。我们的研究结果表明，海洋摄食行为具有功能作用，将 vgll3 的基因组多样性与鲑鱼的成熟年龄联系起来，潜在的年龄依赖性权衡维持着遗传多样性。饮食生态学和成熟年龄之间的共同遗传基础可能使大西洋鲑种群受到海洋生产力自上而下变化引起的进化影响。
