Whole-genome resequencing of Japanese whiting (<i>Sillago japonica</i>) provide insights into local adaptations
Zhiqiang Han, 浙江海洋大学水产学院，浙江 舟山 316002，中国, Xinyu Guo, Qun Liu, Shanshan Liu, Zhixin Zhang, Shijun Xiao, Tianxiang Gao, 青岛华大基因研究院，山东 青岛 266555，中国, 东京海洋大学海洋科学与技术研究院，东京都 港区 108-8477，日本, 西藏自治区农牧科学院水产科学研究所，西藏 拉萨 850000，中国, BGI-Qingdao, BGI-Shenzhen, Qingdao, Shandong 266555, China
Abstract
The genetic adaptations of various organisms to heterogeneous environments in the northwestern Pacific remain poorly understood. Heterogeneous genomic divergence among populations may reflect environmental selection. Advancing our understanding of the mechanisms by which organisms adapt to different temperatures in response to climate change and predicting the adaptive potential and ecological consequences of anthropogenic global warming are critical. We sequenced the whole genomes of Japanese whiting (<i>Sillago japonica</i>) specimens collected from different latitudinal locations along the coastal waters of China and Japan to detect possible thermal adaptations. Using population genomics, a total of 5.48 million single nucleotide polymorphisms (SNPs) from five populations revealed a complete genetic break between the Chinese and Japanese groups, which was attributed to both geographic distance and local adaptation. The shared natural selection genes between two isolated populations (i.e., Zhoushan and Ise Bay/Tokyo Bay) indicated possible parallel evolution at the genetic level induced by temperature. These genes also indicated that the process of temperature selection on isolated populations is repeatable. Moreover, we observed natural candidate genes related to membrane fluidity, possibly underlying adaptation to cold environmental stress. These findings advance our understanding of the genetic mechanisms underlying the rapid adaptations of fish species. Species distribution projection models suggested that the Chinese and Japanese groups may have different responses to future climate change, with the former expanding and the latter contracting. The findings of this study enhance our understanding of genetic differentiation and adaptation to changing environments.