Recent studies have begun to elucidate the genetic basis for phenotypic traits in salmonid species, but many questions remain before these candidate genes can be directly incorporated into conservation management. In Chinook Salmon (Oncorhynchus tshawytscha), a region of major effect for migration timing has been discovered that harbors two adjacent candidate genes (greb1L, rock1), but there has been limited work to examine the association between these genes and migratory phenotypes at the individual, compared to the population, level. To provide a more thorough test of individual phenotypic association within lineages of Chinook Salmon, 33 candidate markers were developed across a 220 Kb region on chromosome 28 previously associated with migration timing. Candidate and neutral markers were genotyped in individuals from representative collections that exhibit phenotypic variation in timing of arrival to spawning grounds from each of three lineages of Chinook Salmon. Association tests confirmed the majority of markers on chromosome 28 were significantly associated with arrival timing and the strongest association was consistently observed for markers within the rock1 gene and the intergenic region between greb1L and rock1. Candidate markers alone explained a wide range of phenotypic variation for Lower Columbia and Interior ocean‐type lineages (29% and 78%, respectively), but less for the Interior stream‐type lineage (5%). Individuals that were heterozygous at markers within or upstream of rock1 had phenotypes that suggested a pattern of dominant inheritance for early arrival across populations. Finally, previously published fitness estimates from the Interior stream‐type lineage enabled tests of association with arrival timing and two candidate markers, which revealed that fish with homozygous mature genotypes had slightly higher fitness than fish with premature genotypes, while heterozygous fish were intermediate. Overall, these results provide additional information for individual‐level genetic variation associated with arrival timing that may assist with conservation management of this species.

中文翻译：

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奇努克鲑鱼成年迁徙时机和适应性候选标记的验证和关联

最近的研究已经开始阐明鲑科物种表型性状的遗传基础，但是在将这些候选基因直接纳入保护管理之前还存在许多问题。在奇努克鲑鱼（Oncorhynchus tshawytscha），发现了一个对迁移时间有重要影响的区域，其中包含两个相邻的候选基因（greb1L，rock1），但与人群相比，研究这些基因与个体迁移表型之间的关联的工作有限，水平。为了提供对奇努克鲑鱼谱系内单个表型关联的更全面测试，在先前与迁移时间相关的28号染色体上的220 Kb区域内开发了33个候选标记。在代表性种群的个体中对候选标记和中性标记进行了基因分型，这些个体在奇努克鲑鱼的三个谱系中的每一个到产卵场的时间上均表现出表型差异。关联测试证实，第28号染色体上的大多数标记与到达时间显着相关，并且始终观察到rock1基因内以及greb1L和rock1之间的基因间区域内的标记之间的最强关联。仅候选标记就解释了下哥伦比亚和内陆海洋型谱系的广泛表型变异（分别为29％和78％），而内陆流型谱系的表型变异较小（5％）。在rock1内或上游标记物杂合的个体具有表型，暗示了群体早期遗传的显性遗传模式。最后，先前发布的来自内部流类型谱系的适应度估计值可以测试到达时间和两个候选标记的关联，这表明具有纯合子成熟基因型的鱼的适应性略高于具有过早基因型的鱼，而杂合子的鱼为中等。总体而言，这些结果为与到达时间相关的个体水平遗传变异提供了更多信息，这可能有助于该物种的保护管理。