华南沿海长鳍篮子鱼不同地理群体的遗传多样性分析

Genetic Diversity Analysis of Different Geographical Populations of Siganus canaliculatus Along the South China Coast

为探明华南沿海长鳍篮子鱼(Siganus canaliculatus)不同地理群体遗传多样性与遗传分化状况,采用线粒体控制区(D-loop)基因序列分析华南沿海厦门(XM)、汕尾(SW)、阳江(YJ)、海口(HK)、三亚(SY)、北海(BH)、钦州(QZ)、防城港(FC)以及越南清化(TH)9个地理位置长鳍篮子鱼群体的遗传多样性及群体遗传结构。结果显示,长鳍篮子鱼群体DNA D-loop序列共计484条,序列长度约828 bp,包含57个变异位点,92个单倍型;所有群体总的单倍型多样性指数(H_(d))为0.80798,核苷酸多样性指数(π)为0.00405;群体内遗传距离为0.00386~0.00532,群体间遗传距离为0.00383~0.00482,群体间分化指数为-0.01935~0.00759,各种分组的AMOVA分析均显示遗传变异全部来自群体内;Fu’s Fs检验值为显著负值(-25.53678,P<0.01),核苷酸错配分布图呈单峰,吻合度检验数值较小且不显著,提示长鳍篮子鱼可能经历过种群扩张事件,推测扩张时间距今1.18万~4.74万年。研究表明,南海北部沿岸及东海南部9个长鳍篮子鱼地理群体间不存在显著的地理结构和谱系结构,可划归一个管理单元进行种质资源保护。

Siganus canaliculatus, belonging to Siganus, Siganidae, Acanthuridae and Perciformes, is widely distributed along the south China coast. It is an important capture and culture fish species in China with high nutrient and economic values. In this study, we analyzed the genetic structure and historical dynamics of nine S. canaliculatus populations from the south China coast, including Xiamen, Shanwei, Yangjiang,Haikou, Sanya, Beihai, Qinzhou, Fangcheng and Thanh Hoa. The genetic diversity and genetic differentiation status of the nine S. canaliculatus populations were explored based on the mitochondrial control region(D-loop) gene sequences. The aim was to provide reference for the conservation and rational exploitation of wild S. canaliculatus germplasm resources and to evaluate the effect of captive breeding and release.From April 2018 to August 2019, a total of 484 wild S. canaliculatus samples were collected from the nine areas investigated and muscle tissue from each specimen was sampled for D-loop sequence amplification.The length of the 484 DNA D-loop sequences was about 828 bp, containing 57 mutation sites and 92 haplotypes. The overall haplotype diversity and nucleotide diversity indices were 0.80798 and 0.00405, respectively, indicating high haplotype diversity and low nucleotide diversity. Genetic distances within the populations were 0.00386~0.00532, and genetic distances between the populations were 0.00383~0.00482, and the total differentiation index between the populations was-0.01935~0.00759. AMOVA analysis shows that the genetic variation of the S. canaliculatus populations nearly occurred within the population. The neutral test shows that Fu’s Fstest value was a significant negative value(-25.53678, P<0.01), the distribution of nucleotide mismatch showed a single peak, and the coincidence test value was small and insignificant, suggesting that S. canaliculatus might have experienced a population expansion event, estimated to occurr about 11 800 years to 47 400 years ago. In summary, there was no significant differentiation of geographic structure and pedigree structure among the nine S. canaliculatus geographical populations in the south China coast, and they can be classified as a management unit for germplasm resource protection.