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测定了广东虎门、广西合浦和广西钦州3个群体45 ind居氏银鱼(Salanx cuvieri)线粒体DNA细胞色素b基因1 017 bp序列片段,发现42个多态位点,28个单倍型。平均单倍型多样性(Hd)和核苷酸多样性(Pi)分别为0.967和0.006,呈现出高单倍型多样性低核苷酸多样性的特点。合浦和钦州群体间遗传分化指数Fst值为-0.029,表明广西的2个群体间没有遗传分化。虎门群体与合浦和钦州群体间的Fst值分别为0.201和0.218,出现中度遗传分化,推测琼州海峡可能阻碍了广东与广西群体间的遗传交流。邻接树上出现2个无明显地理聚群的较弱谱系分支,表明正处于谱系拣选状态。AMOVA分析表明,居氏银鱼群体内遗传差异(86.54%)大于群体间(13.46%)遗传差异,遗传变异主要集中在群体内部。虎门群体中性检测的Tajima’sD为显著负值(-1.847,P=0.018),不对称分布分析呈单峰模式,表明可能在晚更新世(3.2～8.0万年前)经历过种群的快速扩张。建议广东群体和广西群体各作为一个管理保护单位分别加以保护。
A total of 102 polymorphic loci and 28 haplotypes were detected in the mitochondrial DNA 1 017 bp fragment of mitochondrial DNA from 45 populations of Salanx cuvieri in Humen, Guangxi, Hepu, Guangxi and Qinzhou, Guangxi. The average haplotype diversity (Hd) and nucleotide diversity (Pi) were 0.967 and 0.006, respectively, showing the characteristics of high haplotype diversity and low nucleotide diversity. The Fst value of genetic differentiation index between Hepu and Qinzhou populations was -0.029, indicating that there was no genetic differentiation between the two populations in Guangxi. The Fst values of Humen population and Hepu and Qinzhou populations were 0.201 and 0.218, respectively. There was moderate genetic differentiation. It is speculated that the Qiongzhou Strait may hinder the genetic exchange between Guangdong and Guangxi populations. Two weaker lineages with no obvious geographic clustering appear on the adjacent tree, indicating that they are in lineage picking status. The AMOVA analysis showed that the genetic differences (86.54%) in H. yunnanensis population were greater than those in population (13.46%), and the genetic variation mainly concentrated in the inner part of the population. The Tajima’sD for the neutral test in the Humen population was significantly negative (-1.847, P = 0.018), and the unimodal distribution analysis showed a unimodal pattern suggesting that the population may have experienced rapid population growth during the late Pleistocene (3.2-80,000 years ago) expansion. It is suggested that each of the Guangdong and Guangxi groups should be separately protected as a management and protection unit.