Abstract：
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 vgll3LL (the genotype associated with late maturation) tended to forage crustaceans more often than those with vgll3EE (the genotype associated with early maturation), whereas the pattern was reversed in older salmon. Vgll3 LL 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.
摘要：
可遗传表型变异在自由生活人群中的生态作用仍然未知。了解功能性生态过程的遗传基础可以将基因组和表型多样性联系起来，提供对多态性进化以及种群如何应对环境变化的见解。通过量化大西洋鲑鱼的海洋饮食，我们评估了觅食行为如何在个体发育过程中发生变化，与两个基因座的遗传变异有关，对成熟年龄有主要影响（six6和vgll3）。我们使用了两个组件，零膨胀负二项模型，同时量化觅食频率和觅食结果，分别用于鱼类和甲壳类动物的饮食。我们发现，对于两种猎物类型的较老的鲑鱼饲料更活跃（如增加的觅食频率所证明的），但是效率降低（饮食中的猎物减少证明了这一点），表明觅食动力学的年龄依赖性转变。vgll3基因座与觅食行为的年龄依赖性变化有关：具有vgll3LL（与成熟后期相关的基因型）的年轻鲑鱼比具有vgll3EE（与成熟早期相关的基因型）的鲑鱼更频繁地觅食甲壳类动物，而这种模式在较老的鲑鱼中相反。Vgll3LL基因型也与鱼类获取的边际增加有关，尤其是年轻的鲑鱼，而six6不是解释饮食变化的因素。我们的结果表明，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遗传变异。饮食生态与成熟年龄之间的共同遗传基础可能会使大西洋鲑鱼种群受到自下而上的海洋生产力变化引起的进化。
