Key Laboratory of Aquatic Genomics, Ministry of Agriculture, CAFS Key Laboratory of Aquatic Genomics and Beijing, Key Laboratory of Fishery Biotechnology, Chinese Academy of Fishery Sciences, Beijing, 100141, China.
Fujian Collaborative Innovation Centre for Exploitation and Utilization of Marine Biological Resources, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China.
Mar Biotechnol (NY). 2018 Feb;20(1):45-59. doi: 10.1007/s10126-017-9786-0. Epub 2017 Dec 18.
The marine species usually show high dispersal capabilities accompanied by high levels of gene flow. On the other hand, many physical barriers distribute along the continental marginal seas and may prevent dispersals and increase population divergence. These complexities along the continental margin generate serious challenges to population genetic studies of marine species. Chinese sea bass Lateolabrax maculatus distributes broad latitudinal gradient spanning from the tropical to the mid-temperate zones in the continental margin seas of the Northwest Pacific Ocean. Using the double digest restriction-site-associated DNA tag sequencing (ddRAD) approach, we genotyped 10,297 SNPs for 219 Chinese seabass individuals of 12 populations along the Chinese coast in the Northwest Pacific region. Genetic divergence among these populations was evaluated, and population structure was established. The results suggested that geographically distant populations in the Bohai Gulf and the Beibu Gulf retain significant genetic divergence, which are connected by a series of intermediate populations in between. The results also suggested that Leizhou Peninsula, Hainan Island, and Shandong Peninsula are major physical barriers and substantially block gene flow and genetic admixture of L. maculatus. We also investigated the potential genetic basis of local adaptation correlating with population differentiation of L. maculatus. The sea surface temperature is a significantly differentiated environmental factor for the distribution of L. maculatus. The correlation of water temperature and genetic variations in extensively distributed populations was investigated with Bayesian-based approaches. The candidate genes underlying the local selection in geographically divergent populations were identified and annotated, providing clues to understand the potential mechanisms of adaptive evolution. Overall, our genome scale population genetic analysis provided insight into population divergence and local adaptation of Chinese sea bass in the continental marginal seas along Chinese coast.
海洋物种通常表现出较高的扩散能力和高水平的基因流动。另一方面，许多物理障碍分布在大陆边缘海域，可能会阻碍扩散并增加种群分歧。这些大陆边缘的复杂性给海洋物种的种群遗传研究带来了严峻挑战。中国鲈鱼分布广泛，从西北太平洋大陆边缘海域的热带到中温带都有分布。本研究利用双酶切限制位点相关 DNA 标签测序（ddRAD）方法，对西北太平洋地区中国沿海 12 个种群的 219 尾中国鲈鱼个体进行了 10297 个 SNP 基因型分析。评估了这些种群之间的遗传分化，并建立了种群结构。结果表明，渤海湾和北部湾的地理上遥远的种群保持着显著的遗传分化，其间有一系列的中间种群相连。结果还表明，雷州半岛、海南岛和山东半岛是主要的物理障碍，极大地阻碍了中国鲈鱼的基因流动和遗传混合。我们还研究了与中国鲈鱼种群分化相关的局部适应的潜在遗传基础。海面温度是中国鲈鱼分布的一个显著分化的环境因素。本研究采用贝叶斯方法调查了广泛分布的种群中水温与遗传变异的相关性。鉴定并注释了地理上分化种群中局部选择的候选基因，为理解适应进化的潜在机制提供了线索。总的来说，我们的全基因组种群遗传分析深入了解了中国沿海大陆边缘海域中国鲈鱼的种群分化和局部适应。
