中国明对虾的种群遗传结构和地理变异

Genetic Structure and Geographic Variance of the Chinese Shrimp (Fennerpenaeus chinensis) Populations

采用分子系统地理学的研究方法,以烟台群体(YT)、青岛群体(QD)、珠海群体(ZH)(为3个野生群体)以及阳江群体(YJ)(为养殖群体)等4个地理种群的51个中国明对虾个体为实验材料,探讨了中国明对虾地理分布格局的形成原因,并在51个样品中成功扩增出了525 bp的线粒体DNA细胞色素b(m tDNA cyt-b)片段,发现16个变异位点没有插入/缺失,很大程度上倾向于转换(Transition)或颠换(Transversion),Ti/Tv=2.4∶1,变异位点多发生在密码子的第3位点,而密码子的第2位点没有变异位点.在4个地理种群中,共有9种m tDNA单倍型,且均具有较高的单倍型多态性.AMOVA分析发现,各地理区域之间存在显著的遗传分化(62.33%),而区域内和种群内的遗传变异分别只有25.53%和12.14%,种间大部分分子变异是由各地理种群之间单倍型的差异引起的.NJ法构建的系统树显示,9个单倍型被分成黄/渤海地区和南海地区2个明显的类群,这说明2个类群发生了较明显的遗传分化,估计与地理及生殖隔离有关.

In our report,51 F.chinensis samples collected from four geographic populations from Qingdao（QD）,Yantai（YT）,Zhuhai（ZH） and Yangjiang（YJ） were used as materials and molecular phylogeography method were performed to analyze the formation causes of the geographic distribution of Chinese Shrimp（Fennerpenaeus chinensis） populations,from which 525 bp nucleotide fragments of the mitochondrial（mtDNA） cyt-b genes were amplified successfully.The sequencing results indicated that there were no insertion/deletion in 16 mutation nucleotide sites,in which there are many transition and transversion,Ti/Tv=2.4∶1,there are many mutations at the third site,but there are no mutations at 2nd site.There were 9 haplotype in four geographic populations,and their polymorphism was high.Molecular Variance Analysis（AMOVA） results demonstrated that there are significant differentiation（62.33%） among the four geographic populations,which associate with the haplotype polymorphism,25.53% occurred among populations within regions,and 12.14% within populations.A molecular phylogenetic tree constructed with the neighbor-joining（NJ） method suggested that the 9 haplotypes were assigned to two groups associated with geographic regions,which indicated that that there are significant differentiation,which is associated with spatial separation.