基于mt COI、Cyt b、D-loop序列的南方多鳞鱚群体遗传结构分析

Genetic Structure of Four Sillago sihama Populations in Southern China Based on Mitochondrial Sequences

分析中国南部沿海多鳞鱚4个野生群体的遗传多样性,为多鳞鱚种质资源保护及合理开发利用提供理论参考。基于线粒体COI、Cyt b、D-loop基因序列对福建厦门(XM)、广东阳江(YJ)、海南海口(HK)和广西北海(BH)的4个多鳞鱚(Sillago sihama)群体进行遗传结构分析。经PCR扩增和测序获得4个多鳞鱚群体195条线粒体COI+Cyt b+D-loop片段序列。结果表明,单倍型多样性指数(Hd)为0.88266~0.98785,核苷酸多样性指数(π)为0.00098~0.00257,整体H_(d)与π分别为0.92784和0.00158。遗传分化系数(F_(st))和基因流(N_(m))分别为0.00075~0.14888和1.429205~333.0833。将4个地理群体分成不同组合进行AMOVA分子方差分析,结果显示,4个群体内变异比例为93.33%,南海群体和东海群体的组内变异比例为86.57%,琼州海峡东西群体的组内变异比例为94.49%。基于COI、Cyt b和D-loop的分析结果,厦门群体和北海、海口、阳江群体间存在中等程度的遗传分化,可作为两个管理保护单位进行保护。

Sillago sihama,commonly known as the sardine,was an important economic species of coast?al fishing communities.To restore S.sihama populations,captive breeding and release has been used since successful artificial breeding was accomplished in 2012.In this study,we analyzed the genetic structure of four S.sihama populations in Xiamen,Fujian(XM);Yangjiang,Guangdong(YJ);Haikou,Hainan(HK)and Beihai,Guangxi(BH),based on mitochondrial control region(COI,Cyt b,and D-loop)gene sequenc?es.In January and June 2019,a total of 195 wild S.sihama specimens were collected from the four study areas.Mitochondrial COI+Cyt b+D-loop sequences from the four S.sihama populations were obtained by PCR amplification and sequencing,with respective lengths of 1274 bp,1141 bp and 362-363 bp.The ranges of the haplotype diversity index(H_(d))and nucleotide diversity(π)index of the three gene sequences were,respectively,0.88266-0.98785 and 0.00098-0.00257,with average values of 0.92784 and 0.00158The ranges of the genetic differentiation coefficient(F_(st))and gene flow(N_(m))of the four populations were respectively,0.01185-0.14888 and 1.429205-333.0833.The four populations were classified according to their geographic positions,and the analysis of molecular variance(AMOVA)showed that genetic varia?tion originated primarily within the populations,with proportions of variation of 93.33%within the four populations(BH,HK,YJ,XM),86.57%between the south China sea groups(BH,HK,YJ)and east China sea group(XM),and 94.49%between the groups of the east Qiongzhou Straits(BH,HK)and wes Qiongzhou Straits(YJ,XM).In summary,there was a moderate degree of genetic differentiation between the Xiamen population and the Beihai,Haikou,and Yangjiang populations that should be protected as two management units.This study provides a reference for the conservation and rational exploitation of S.sihama germplasm resources in south China coast.