Kusche Henrik, Côté Guillaume, Hernandez Cécilia, Normandeau Eric, Boivin-Delisle Damien, Bernatchez Louis
Département de BiologieInstitut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec QC Canada.
Present address: Thünen Institute of Fisheries Ecology Hamburg Germany.
Ecol Evol. 2017 Jun 17;7(15):5797-5807. doi: 10.1002/ece3.3132. eCollection 2017 Aug.
Age at maturity is a key life-history trait of most organisms. In anadromous salmonid fishes such as Atlantic Salmon (), age at sexual maturity is associated with sea age, the number of years spent at sea before the spawning migration. For the first time, we investigated the presence of two nonsynonymous polymorphisms in North American Atlantic Salmon populations that relate to sea age in European salmon and quantified the natural variation at these and two additional candidate SNPs from two other genes. A targeted resequencing assay was developed and 1,505 returning adult individuals of size-inferred sea age and sex from four populations were genotyped. Across three of four populations sampled in Québec, Canada, the late-maturing component (MSW) of the population of a given sex exhibited higher proportions of SNP genotypes 54Thr and 323Lys compared to early-maturing fish (1SW), for example, 85% versus 53% of females from Trinité River carried 323Lys ( = 205 vs. = 30; .001). However, the association between polymorphism and sea age was more pronounced in females than in males in the rivers we studied. Logistic regression analysis of SNP genotypes revealed increased probabilities of exhibiting higher sea age for 54Thr and 323Lys genotypes compared to alternative genotypes, depending on population and sex. Moreover, individuals carrying the heterozygous SNP genotypes were more likely (>66%) to be female. In summary, two nonsynonymous polymorphisms were confirmed in North American populations of Atlantic Salmon and our results suggest that variation at those loci correlates with sea age and sex. Our results also suggest that this correlation varies among populations. Future work would benefit from a more balanced sampling and from adding data on juvenile riverine life stages to contrast our data.
成熟年龄是大多数生物关键的生活史特征。在诸如大西洋鲑等溯河产卵的鲑科鱼类中，性成熟年龄与海龄相关，即产卵洄游前在海中度过的年数。我们首次在北美大西洋鲑种群中调查了与欧洲鲑海龄相关的两个非同义多态性的存在情况，并对这两个多态性位点以及另外两个来自其他基因的候选单核苷酸多态性（SNP）的自然变异进行了量化。我们开发了一种靶向重测序分析方法，并对来自四个种群的1505条洄游成年个体进行了基因分型，这些个体的海龄和性别可通过体型推断。在加拿大魁北克采样的四个种群中的三个种群中，给定性别的种群中晚熟部分（MSW）与早熟鱼类（1SW）相比，SNP基因型54Thr和323Lys的比例更高，例如，特里尼蒂河85%的雌性携带323Lys，而早熟雌性为53%（=205对=30；P<0.001）。然而，在我们研究的河流中，该多态性与海龄之间的关联在雌性中比在雄性中更为明显。对SNP基因型的逻辑回归分析显示，与其他基因型相比，54Thr和323Lys基因型表现出更高海龄的概率增加，这取决于种群和性别。此外，携带杂合SNP基因型的个体更有可能（>66%）为雌性。总之，在北美大西洋鲑种群中确认了两个非同义多态性，我们的结果表明这些位点的变异与海龄和性别相关。我们的结果还表明这种相关性在不同种群中有所不同。未来的研究将受益于更均衡的采样，并增加幼鱼河流生活阶段的数据以对比我们的数据。
