Data from: Mapping and expression of candidate genes for development rate in rainbow trout (Oncorhynchus mykiss)

Development rate has important implications for individual fitness and physiology. In salmonid fishes, development rate correlates with many traits later in life, including life history diversity, growth, and age and size at sexual maturation. In rainbow trout (Oncorhynchus mykiss), a Quantitative Trait Locus (QTL) for embryonic development rate has been detected on chromosome 5 across populations. However, few candidate genes have been identified within this region. In this study, we use gene mapping, gene expression, and quantitative genetic methods to further identify the genetic basis of embryonic developmental rate in O. mykiss. Among the genes located in the region of the major development rate QTL (GHR1, Clock1a, Myd118-1, and their paralogs), all were expressed early in embryonic development (fertilization through hatch), but none were differentially expressed between individuals with the fast- or slow-developing alleles for a major embryonic development rate QTL. In a follow up study of migratory and resident rainbow trout from natural populations in Alaska, we found significant additive variation in development rate, and moreover found associations between development rate and allelic variation in all three candidate genes within the QTL for embryonic development. The mapping of these genes to this region and associations in multiple populations provide positional candidates for further study of their roles in growth, development, and life history diversity in this model salmonid.发育速率对个体适合度与生理机能具有重要意义。在鲑科鱼类中，发育速率与后续生命阶段的诸多性状密切相关，包括生活史多样性、生长表现以及性成熟时的年龄与体型。在虹鳟（Oncorhynchus mykiss）中，研究团队已在多个种群的5号染色体上检测到与胚胎发育速率相关的数量性状基因座（Quantitative Trait Locus, QTL），但该区域内鲜有被确认的候选基因。本研究借助基因定位、基因表达分析以及数量遗传学方法，进一步解析虹鳟（O. mykiss）胚胎发育速率的遗传基础。位于主效发育速率QTL区域内的基因（包括GHR1、Clock1a、Myd118-1及其旁系同源基因），均在胚胎发育早期（从受精至孵化阶段）得以表达，但携带该主效胚胎发育速率QTL的快发育等位基因与慢发育等位基因的个体之间，未出现上述基因的差异表达情况。针对阿拉斯加自然种群中的洄游型与定居型虹鳟开展的后续研究中，我们发现发育速率存在显著的加性遗传变异，且进一步发现发育速率与胚胎发育QTL区域内全部3个候选基因的等位基因变异存在显著关联。将上述基因定位至该QTL区域，结合多种群中的关联分析结果，可为进一步研究这类基因在这一模式鲑科鱼类的生长、发育以及生活史多样性中的功能提供定位候选基因。