南盘江破碎生境中子陵吻虾虎鱼的遗传多样性

Genetic Diversity of Goby Rhinogobius giurinus in the Fragmented Habitat in Nanpan River

众多的水利设施和附属高原湖泊引起南盘江流域出现严重的生境破碎。以子陵吻虾虎鱼作为研究对象,探讨南盘江流域破碎化的生境对鱼类种群遗传多样性的影响。子陵吻虾虎鱼因经济价值低而未被人工驯化,可作为评估生境破碎化影响的理想物种。以线粒体细胞色素b(Cyt b)基因和细胞色素c氧化酶第Ⅰ亚基(COXⅠ)基因作为分子标记,对来自南盘江水系13个隔离种群子陵吻虾虎鱼的遗传多样性和遗传结构进行分析。在13个种群194尾子陵吻虾虎鱼的COXⅠ基因、Cyt b基因及联合线粒体基因中观察到了27、22、49个变异位点和11、13、26个单倍型,平均单倍型多样性和核苷酸多样性分别为0.691、0.813、0.881和0.0053、0.0060、0.0056。系统发育树结果均显示,子陵吻虾虎鱼的13个群体聚类为2个进化分支,但并未出现明显的地理聚类现象。分子方差分析结果表明,子陵吻虾虎鱼群体的遗传变异主要来自种群间。上述结果表明,南盘江破碎生境中的子陵吻虾虎鱼群体呈现出了较高的遗传多样性和显著的遗传分化。可能因较强的生存适应能力及稳定的有效种群大小,子陵吻虾虎鱼呈现出了较高的遗传多样性水平,同时又在较弱的迁移能力和破碎化生境的隔离效应的共同影响下,导致了子陵吻虾虎鱼种群间显著的遗传分化。

Multiple water conservancy facilities and the associated lakes result in fragmented habitats in Nanpan River areas.We investigated the effect of fragmented habitats on the population genetic diversity of goby Rhinogobius giurinus.Since the goby has never been domesticated because of low economic value,this species is suitable for evaluating the effect of fragmented habitats.Mitochondrial COXⅠgene and Cyt b gene were used as molecular markers for the analysis of the genetic diversity and differentiation of goby populations from 13 plateau lakes of the Nanpan River.In the COXⅠgene,Cytb gene and combined mitochondrial DNA sequences,27,22,49 variable sites and 11,13,26 haplotypes were observed among 194 individuals belonging to 13 goby populations,with average haplotype diversity of 0.691,0.813,0.881 and nucleotide diversity of 0.0053,0.0060,0.0056.The phylogenetic trees showed that 13 populations of goby were divided into two branches without obvious phylogeographic pattern.The analysis of molecular variance(AMOVA)showed that the genetic differentiation mainly occurred among populations.Overall,it was found that the goby in the fragmented habitats of Nanpan River had high genetic diversity as well as obvious genetic differentiation.Probably due to strong adaptability and stable effective population size,the goby displayed a high level of genetic diversity.Besides,both weak migration ability and fragmented habitats led to significant genetic differentiation of the goby.