基于线粒体16SrRNA基因序列的长江下游重要水体脆弱象鼻溞群体遗传结构分析

摘要

This study aims to investigate the genetic structure of B.fatalis from 10 water bodies from the lower reaches of the Yangtze River.By using mitochondrial 16SrRNA, 100 individuals were sequenced and analyzed.The results showed that 8 variable sites were detected, and 9 haplotypes were defined based on the 16SrRNA sequences.It indicated a lower haplotype diversity (Hd=0.284)and nucleotide diversity (Nd=0.000 76) in these populations.Molecular variance analysis (AMOVA) demonstrated that most variation was explained by "within populations" (93.33%), and there is no significant variation among populations (6.67%).The Fst revealed no significant difference among all water bodies.Haplotypes dispersed in different populations showed no obvious geographical structure in the phylogenetic tree and haplotype network.Neutrality and mismatch distribution test indicated that there was recent population expansion of B.fatalis in spatial scales.%为了解长江下游地区10个水体脆弱象鼻溞群体的遗传结构,研究测定了脆弱象鼻溞(Bosmina fatalis)线粒体16SrRNA基因序列,结果显示,100个样本中共有8个变异位点,定义了9个单倍型,单倍型多样性(Hd=0.284)和核苷酸多样性(Nd=0.00076)均较低.AMOVA分子变异分析结果表明,脆弱象鼻溞遗传分化主要来自群体内,占93.33%,群体间的变异低,占6.67%.Fst值统计检验表明,各水体之间遗传分化不显著.系统发育树和中介网络图说明脆弱象鼻溞单倍型间关系较近,未形成明显谱系地理格局.中性检验和错配分布结果说明脆弱象鼻溞出现过群体扩张现象.