基于COⅠ序列的海南岛8个弹涂鱼群体遗传多样性研究

Genetic diversity based on mitochondrial COⅠgene sequences in eight populations of Periophthalmus modestus in the Hainan Island

使用线粒体COⅠ基因部分序列作为遗传标记,分析了中国海南岛8个弹涂鱼(Periophthalmus modestus)地理群体的遗传多样性、遗传分化、种群历史动态,以为更好的保护弹涂鱼种质资源提供依据。采集的236尾弹涂鱼样本的COⅠ基因片段序列共检测到59种单倍型,总体单倍型多样性较高(0.861±0.019),核苷酸多样性偏低(0.00439±0.00024);基于单倍型的邻接关系树没有呈现与地理群体成谱系的结构;分子方差分析表明,遗传变异主要来自群体内(99.36%);遗传分化指数(Fst)显示,三亚与临高、东方两个群体存在中等程度遗传分化;群体间基因交流频繁,核苷酸不配对分布和中性检验表明,部分地方群体曾经发生过扩张。海南岛弹涂鱼整体遗传分化程度不高(Fst=0.00637),是一个随机交配的群体,遗传多样性较低,建议加强弹涂鱼资源的保护。

Genetic diversity of fishes as an important part of biodiversity plays an important role in the conservation and sustainable exploitation of fishery resources. Periophthalmus modestus has high economic value and unique ecological value.Mitochondrial COⅠgene of eight populations(Haikou, Chengmai, Lingao, Danzhou, Changjiang, Dongfang, Ledong, Sanya) were amplified by general PCR technology to analyze the genetic diversity, genetic structure and demographic history to protect P. modestus resources. We obtained 236 COⅠ genes with a length of 621 bp from the eight locations in the Hainan Island, and a total of 54 mutation sites, 29 parsimony information sites and 59 haplotypes were detected. In these fragment sequences the base content of A, T, G and C was 31.2%,26.3%,26.0% and 16.4% respectively, the content of A + T( 57.5%) was higher than that of G + C(42.4%).The population of P. modestus in the Hainan Island had high haplotype diversity(0.861±0.019) and low nucleotide diversity(0.004 39±0.000 24).No obvious geographical structure was found in neighbor-joining tree or haplotype network.AMOVA analysis suggested that genetic variation within populations(99.36%) was larger than that among populations(0.64%), indicating that genetic divergence was mainly distributed within populations.Fst value among eight populations ranged from-0.023 54 to 0.060 42, showing that a moderate degree of genetic differentiation existed between Sanya and the populations of Lingao, Dongfang. Gene exchanges between different groups were frequent. Both mismatch distribution analysis and neutrality tests indicated a possible expansion in some local groups(Haikou, Lingao, Danzhou, Changjiang, Sanya). The genetic expansion happened possibly during the Quaternary Period, and may be significantly affected by the glacial-interglacial cycles.The results of this paper demonstrated that overall population of P. modestus in the Hainan Island did not have significant genetic differentiation(Fst=0.006 37). It was a panmixia and some local groups had experienced expansion. The total population of P.modestus in the Hainan Island had low genetic diversity. It is recommended to strengthen the protection of P. modestus resources.