Data from: Evolution of sex determination loci in Atlantic salmon

Teleost fish exhibit a remarkable diversity in the control of sex determination, offering the opportunity to identify novel differentiation mechanisms and their ecological consequences. Here, we perform GWAS using 4715 fish and 46,501 SNP to map sex determination to three separate genomic locations in Atlantic salmon (Salmo salar). To characterize each, whole genome sequencing was performed to 30-fold depth of coverage using 20 fish representing each of three identified sex lineages. SNP polymorphism reveals male fish carry a single copy of the male specific region, consistent with an XX/XY or male heterogametric sex system. Haplotype analysis revealed deep divergence between the putatively ancestral locus on chromosome 2, compared with loci on chromosomes 3 and 6. Haplotypes in fish carrying either the chromosome 3 or 6 loci were nearly indistinguishable, indicating a founding event that occurred following the speciation event that defines defined Salmo salar from other salmonids. These findings highlight the evolutionarily fluid state of sex determination systems in salmonids, and resolve to the sequence level differences in animals with divergent sex lineages.

硬骨鱼（Teleost fish）的性别决定调控机制展现出显著的多样性，为发掘全新的性别分化机制及其生态效应提供了宝贵的研究契机。本研究以大西洋鲑（Salmo salar）为研究对象，利用4715尾样本与46501个单核苷酸多态性（Single Nucleotide Polymorphism, SNP）标记开展全基因组关联分析（Genome-Wide Association Study, GWAS），将性别决定位点定位至三个独立的基因组区域。为解析这三个区域的特性，研究针对三个已鉴定的性别谱系各选取20尾个体进行全基因组测序，测序覆盖深度达30倍。单核苷酸多态性分型结果显示，雄性个体仅携带一份雄性特异性区域，与XX/XY型或雄性异配性别决定系统的特征相符。单倍型分析结果表明，2号染色体上的推定祖先位点与3号、6号染色体上的性别决定位点之间存在深度序列分化。携带3号或6号染色体性别位点的个体，其单倍型几乎无法区分，提示该奠基事件发生在大西洋鲑从其他鲑科鱼类分化形成之后。本研究结果凸显了鲑科鱼类性别决定系统在演化过程中的高度可塑性，并明确了不同性别谱系个体间的序列层面差异。