Christensen Kris A, Flores Anne-Marie, Joshi Jay, Shibata Kiko, Fujimoto Takafumi, Koop Ben F, Devlin Robert H
Department of Biology, University of Victoria, Victoria, British Columbia, Canada V8W 2Y2.
Faculty and Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan.
G3 (Bethesda). 2025 Feb 5;15(2). doi: 10.1093/g3journal/jkae278.
Masu salmon (Oncorhynchus masou) are the only Pacific salmon endemic to Asia. Some researchers prefer to categorize these salmon into 4 subspecies (masu-Oncorhynchus masou masou, amago-Oncorhynchus masou ishikawae, Biwa-Oncorhynchus masou subsp., and Formosan-Oncorhynchus masou formosanus), while others prefer individual species designations. Even though the masu salmon fishery is thousands of years old, classification of the diversity within the masu salmon species complex remains elusive. In this study, a genetic map and reference genome assembly were generated for 1 species/subspecies (masu) to provide resources for understanding the species complex. In O. m. masou, the sex chromosome was determined to be chromosome 7. Resequenced genomes from 2 other putative subspecies (amago and Biwa) provided evidence that they do not share the same sex chromosome. Principal component and admixture analyses clustered the amago and Biwa salmon close together. This supported previous findings of a close relationship between amago and Biwa salmon and a more distant relationship to masu salmon for both. Additional analyses of the masu salmon species complex will benefit from using the new reference genome assembly.
马苏大麻哈鱼（Oncorhynchus masou）是亚洲特有的唯一太平洋鲑鱼。一些研究人员倾向于将这些鲑鱼分为4个亚种（马苏大麻哈鱼—Oncorhynchus masou masou、石川马苏大麻哈鱼—Oncorhynchus masou ishikawae、琵琶湖马苏大麻哈鱼—Oncorhynchus masou subsp.和台湾马苏大麻哈鱼—Oncorhynchus masou formosanus），而另一些人则倾向于将它们视为独立的物种。尽管马苏大麻哈鱼渔业已有数千年历史，但马苏大麻哈鱼种复合体内部的多样性分类仍然难以捉摸。在本研究中，为1个物种/亚种（马苏大麻哈鱼）构建了遗传图谱和参考基因组组装，以提供了解该种复合体的资源。在马苏大麻哈鱼指名亚种（O. m. masou）中，确定性染色体为7号染色体。对另外两个假定亚种（石川马苏大麻哈鱼和琵琶湖马苏大麻哈鱼）的重测序基因组提供了证据，表明它们不共享相同的性染色体。主成分分析和混合分析将石川马苏大麻哈鱼和琵琶湖马苏大麻哈鱼聚类在一起。这支持了之前的研究结果，即石川马苏大麻哈鱼和琵琶湖马苏大麻哈鱼之间关系密切，而它们与马苏大麻哈鱼的关系较远。对马苏大麻哈鱼种复合体的进一步分析将受益于使用新的参考基因组组装。
