华南3个赤眼鳟群体Cytb基因的遗传变异

Genetic variation of mitochondrial cytochrome b of 3 Squaliobarbus curriculus populations in South China

测定了珠江和韩江3个群体21尾赤眼鳟线粒体细胞色素b基因1 029 bp序列片段,发现11个单倍型,14个变异位点。韩江群体单倍型多样度h(0.464)和核苷酸多样度π(0.000 97)较低,珠江水系左江和郁江群体较高(h=0.929-1,π=0.023 6-0.036 9)。在邻接树上不同地理来源的个体混杂,没有明显的谱系结构和地理聚群。Fst值和AMOVA分析亦显示珠江与韩江群体之间没有显著遗传分化。单倍型网络图呈星状结构,中性检测Tajima’s D和Fu’s Fs均为显著负值,核苷酸不对称分布分析呈单峰模式,说明华南赤眼鳟群体可能在晚更新世(164-66KaBP)曾经历过种群的快速扩张。

One thousand and twenty nine bp sequence of partial rnitochondrial cytochrome b gene of 21 individuals representing 2 populations in the Pearl River（PR） system and 1 population in Han River（HR） in South China was sequenced, and 11 haplotypos and 14 variable sites were detected. Haplotype diversity（h） and nucleotide diversity（π） were much lower in population from HR （h=0.464 and π=0.000 97） than those in populations from Zuojiang and Yujiang in the PR system（h=0.929-1,π=0.023 6-0.036 9）. Individuals from different locations in neighbor-joining tree were intertwined showing neither genealogical nor geographic clusters. Pairwise comparison of Fst and AMOVA analysis indicated that there was no significant genetic divergence among 3 populations. As expected from star-like networks, Fs tests and Tajima＇s D tests of whole population were significantly negative, and mismatch distributions were unimodal, indicating a Pleistocene population expansion at about 164 000-66 000 KaBP.