大鳞副泥鳅群体线粒体DNA D-loop序列遗传变异分析

Genetic Variations in Mitochondrial DNA D-loop Sequence of Large Scale Loach Paramisgurnus dabryanus

为探明大鳞副泥鳅野生资源状况,利用线粒体DNA D-loop序列,对天津5个大鳞副泥鳅自然群体的遗传多样性、遗传结构及种群历史动态进行分析。5个群体72个个体的D-loop基因序列全长912~914bp,其中多态性位点30个,共检测到22个单倍型,平均单倍型多样性和核苷酸多样性分别为0.813和0.0015,呈现高单倍型多样性和低核苷酸多样性的模式。5个群体间的遗传分化指数为-0.0205~0.0795,总的遗传分化指数为0.0712,属中等程度的遗传分化。单倍型网络进化图和单倍型系统发育树均未显示出明显的地理分布格局,中性检验和核苷酸不配对分布分析均表明,大鳞副泥鳅经历过种群扩张,扩张事件发生在第四纪更新世晚期。研究结果表明,应加强5个湿地大鳞副泥鳅群体的保护,适时开展大鳞副泥鳅良种选育工作,减少对大鳞副泥鳅野生资源的破坏。

In order to understand the current situation of wild resources for large scale loach Paramisgurnus dabryanus,the genetic diversity,genetic structure and historical dynamics of five populations in Tianjin were analysed by sequencing the D-loop genes in the mitochondrial DNA.The full sequences of D-loop genes of 72 individual samples were 912-914 bp,of which 30 mutations of nucleotide acids and 22 haplotypes were identified,with haplotype diversity of 0.813 and mean nucleotide diversity of 0.0015.The analysis of D-loop genes from the five large scale loach populations showed a high haplotype diversity and low nucleotide diversity pattern.The fixation indices(Fst)among the five populations were varied from-0.0205 to 0.0795 and the total Fst value was 0.0712,showing a moderate level of genetic differentiation.Haplotype network and phylogenetic trees of the five large scale loach populations revealed that there was no clear geographic distribution pattern.Both neutrality tests and mismatch distribution analysis suggested a late Pleistocene population expansion for the five populations.The findings show that the protection of the five large scale loach populations should be strengthened,and that the breeding work should be carried out in time to reduce the destruction of the wild resources of the large scale loach.