基于线粒体基因nd5对长江上游黑尾近红鲌遗传多样性分析

Genetic Diversity Analysis of Ancherythroculter nigrocauda in the Upper Reaches of the Yangtze River Based on Mitochondrial Gene nd5 Squences

【目的】了解长江上游黑尾近红鲌野生群体遗传资源现状。【方法】采用线粒体基因nd5序列分析法对采集自龙溪河(LOR)、濑溪河(LAR)和长江干流合江段(HJ)的89个黑尾近红鲌样本的遗传多样性和遗传结构进行了分析。【结果】PCR扩增和产物测序后,获得1 668 bp黑尾近红鲌nd5序列,各种群序列碱基组成均表现出明显的A+T偏倚性。多态性遗传参数分析显示,89尾个体中共检测到6个单倍型,干流种群特有单倍型数量明显高于支流种群。各群体均呈现高单倍型多样性(0.571~0.662)和低核苷酸多样性(0.000 45~0.000 69)的特征,且支流种群(LOR,LAR)核苷酸多样性低于干流种群(HJ)。Fst值和系统进化分析结果表明,黑尾近红鲌支流种群和干流种群已有显著的遗传分化。【结论】支流种群也具有保护的重要性,干流种群和支流种群可以作为不同遗传单元进行保护。

【Objective】The objective of this study was to understand the current statues of Ancherythroculter Nigrocauda genetic resources in the upper reaches of the Yangtze River.【Method】Genetic diversity and structure of Ancherythroculter nigrocauda populations were assessed by mitochondrial NADH dehydrogenase subunit 5 (nd5) among 89 individuals,which were collected from three geographic distinct ranges of the upper Yangtze River including Longxi River (LOR),Laixi River (LAR),and Hejiang range of Yangtze River (HJ).【Result】1 668 bp sequence of nd5 was obtained after PCR amplification and product sequencing,the nucleotide compositions of three populations all were A+T-biased. The genetic diversity indices showed that 6 haplotypes were detected in 89 individuals,Further haplotype analysis revealed a high haplotype diversity (0.571~0.662) and a low nucleotide diversity (0.000 45~0.000 69) among these three wild populations. The nucleotide diversity of the populations (LOR,LAR) in the tributaries were lower than that the population in the main stream,and the number of endemic haplotypes in the main stream population was significantly higher than that in the tributary population. The results of Fst and phylogenetic analysis showed that there was significant genetic differentiation between the tributaries and the main stream populations of A. nigrocauda.【Conclusion】Therefore,it is considered that the tributary populations were also important for conservation,the main stream population and the tributary populations can be protected as different genetic units.