大尺度温度选择压力下玉筋鱼种群遗传变异格局研究

Temperature is one of the important factors limiting distribution of marine organisms. There is no systematic study to evaluate the temperature stress in shaping population genetic strucure of marine organisms. There are different ocean currents in Northwestern Pacific. The representative ocean currents in this area are Kuroshio Current, Oyashio Current and Tsushima Current. Different current systems have obvious difference temperature stress. In this project, we use a common cold water species Ammodytes personatus as model species. Considering the previous mtDNA research, the mtDNA protein-coding genes, HSP70 gene and AFLP markers are applied to study the temperature stress in shaping the genetic diversity of this species, compare the ratio of the rates of nonsynonymous to synonymous substitutions (Ka/Ks) among populations, and distribuiton of polymorphic sites in HSP70 gene, indicating the influence of temperature stress on the evultion of mtDNA and HSP70 gene. Whether the mixed zone between Kuroshio Current and Oyashio Current is effective physicla barrier will be tested. The research result could help us to understand evolution mechanism of cold water species, protect the marine ecological system and maintain the sustainable development of fishery production.

温度是限制海洋生物分布的重要因素，在群体水平上温度选择压力对海洋生物遗传进化存在如何影响尚无系统研究。西北太平洋区具有多样的洋流系统，代表性的有黑潮暖流、亲潮暖流及其交汇区和对马暖流，不同的洋流系统具有明显差异的温度等环境特征。本项目计划以西北太平洋区常见冷温性鱼类玉筋鱼为模式种，运用线粒体DNA蛋白质编码基因、HSP70基因、核基因AFL等分子标记并结合环境因子和生物学资料分析，通过比较不同地理群体中线粒体蛋白质编码基因同义突变/非同义突变比率、HSP70基因多态性定量分析长时间温度选择压力对于线粒体DNA和HSP70基因进化影响，检验黑潮和亲潮交汇区是否核基因的隔离屏障，为以后阐明海洋鱼类适应温度变化的机制提供基础。本研究成果从群体水平系统阐述温度选择压力对线粒体DNA和HSP70基因进化影响，并推演全球环境变暖对玉筋鱼现有种群分布

本项目用线粒体蛋白质编码基因、HSP70基因、 AFLP和微卫星技术为分子标记，对玉筋鱼遗传结构进行了研究，发现玉筋鱼存在两个基因隔离的隐蔽种，洋流交汇区是两个种的隔离屏障，洋流带来的温度梯度促进了两个的分化，两个隐蔽种的分界线在14℃等温线附近。全球气温持续上升将对玉筋鱼两种群分布将产生重要影响。此外南北的不同温度造成了玉筋鱼南北种群受到不同的选择压力，在南方种群，线粒体DNA受到选择压力小，易形成新的同义突变；在北方种群，线粒体DNA受到低温的胁迫，同义突变较低。本项目研究揭示了温度对海洋生物遗传分化的影响，为基于种群的渔业资源管理和全球变化预测研究提供了理论支持。本项目已正式发表论文SCI收录期刊论文4篇，SCI刊物录用论文3篇；已完成项目的各项研究指标。