基于线粒体控制区序列的光裸方格星虫群体遗传多样性分析  

Population genetic diversity analysis of Sipunculus nudus based on mtDNA control region sequences

作　　者：彭银辉[1] 周于娜 刘旭佳[1] 黄国强[1,3] 蔡小辉 潘英 

机构地区：[1]广西海洋研究所,广西海洋生物技术重点实验室,广西北海536000 [2]广西大学动物科学技术学院,广西南宁530004 [3]钦州学院海洋学院,海洋生命科学与技术研究中心,广西钦州535011

出　　处：《水产学报》2017年第10期1542-1551,共10页Journal of Fisheries of China

基　　金：国家自然科学基金(31160532);广西科学研究与技术开发计划项目(桂科攻14121006-2-1);广西自然科学基金(2015GXNSFBA139081);广西科学院基本科研业务费(15YJ22HYS13)~~

摘　　要：为了解光裸方格星虫的群体遗传结构和种质资源状况,对北部湾海域光裸方格星虫6个地理野生群体(广西北海、湛江、钦州、防城港、海南儋州,以及越南海防)共93个个体的线粒体DNA(mtDNA)控制区序列进行分析。共检测到107个变异位点,定义了85个单倍型,序列对AT有明显的偏倚性,群体总的单倍体多样性(Hd)和核苷酸多样性(Pi)分别为0.998和0.018 89。单倍型邻接聚类树分析6个群体无明显分支,各单倍型分布于单倍型网络中介图中亦没有明显的地理分支。各群体间的遗传分化系数Fst值为–0.018 13~0.028 05,遗传分化极不明显,AMOVA分析显示光裸方格星虫的遗传差异主要来自群体内(99.74%)。中性检验Tajima’s D和Fu’s Fs值均为负值,核苷酸不配对分布图呈明显的单峰形,提示光裸方格星虫群体在历史上曾出现群体扩张,推算出扩张时间为距今171万年前。目前光裸方格星虫仍具有较高的遗传多样性,6个地理群体间无明显遗传分化,存在频繁的基因交流,推测种群在早更新世曾出现群体扩张。In order to study the population genetic structure and germplasm resources of the Sipunculus nudus.mtDNA control region sequences of S. nudus of six geographic populations along the coast of Beibu Gulf（Beihai,Zhanjiang, Qinzhou, Fangchenggang, Danzhou of China and Haiphong of Vietnam） were analyzed. Results showed that a total of 93 control region sequences with 107 variable sites and 85 haplotypes were obtained, and an evident AT-skew was found in mtDNA control region sequences of S. nudus; the haplotype diversity（Hd） and nucleotide diversity（Pi） were 0.998 and 0.018 89 respectively. The NJ（Neighbor Joining） tree base on haplotype showed that the six populations presented no obvious branches, and all haplotypes were randomly distributed in the haplotype network. The range of fixation index（Fst） of different populations was –0.018 13–0.028 05, and the genetic differentiation among populations was not obvious. The results of AMOVA revealed that the genetic variance mainly occurred within populations（99.74%）. In terms of the negatively selective neutrality test and mismatch distribution of pairwise, we could suggest that a population expansion occurred in S. nudus, and the estimated time was about 1 710 000 years ago. The results indicated that there was high genetic diversity in S.nudus and existed gene exchange among populations, and the estimated population expansion could occur during the Early Pleistocene.

关 键 词：光裸方格星虫 遗传结构 线粒体控制区 北部湾 

分 类 号：Q347[生物学—遗传学] S917.4[农业科学—水产科学]