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长江上游小眼薄鳅线粒体DNA遗传多样性

申绍祎2,田辉伍1,刘绍平1,陈大庆1,吕浩3,汪登强1*#br#   

  1. (1中国水产科学院长江水产研究所, 农业部长江中上游渔业资源环境科学观测实验站, 武汉 430223; 2西南大学生命科学
    学院, 重庆 400715; 3西南大学动物科技学院, 重庆 400715)
  • 出版日期:2017-10-10 发布日期:2017-10-10

Genetic diversity of Leptobotia microphthalma in the upper Yangtze River inferred from mitochondrial DNA.

SHEN Shao-Yi2, TIAN Hui-Wu1, LIU Shao-Ping1, CHEN Da-Qing1, LV Hao3, WANG Deng-Qiang1*#br#   

  1. (1Scientific Observing and Experimental Station of Fishery Resources and Environment in the Upper and Middle Reaches of the Yangtze River, Ministry of Agriculture, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China; 2School of Life Science, Southwest University, Chongqing 400715, China; 3School of Animal and Technology, Southwest University, Chongqing 400715, China).
  • Online:2017-10-10 Published:2017-10-10

摘要:

小眼薄鳅是长江上游特有的小型鱼类,自然分布狭窄。本研究采用线粒体细胞色素b (cytochrome b, cyt-b)和控制区序列,对长江上游江津段和岷江下游宜宾段两个群体共108尾小眼薄鳅 (Leptobotia microphthalma) 样本的遗传多样性和遗传结构进行了分析。结果表明:小眼薄鳅群体cyt-b序列共检出28个多态位点,34种单倍型,平均单倍型多样性指数(Hd)和核苷酸多样性指数(Pi)分别为0.889和0.00382;控制区序列共检出变异位点49个,单倍型65种,Hd指数和Pi指数分别为0.958和0.00420。分子方差分析(AMOVA)显示:小眼薄鳅采样点群体内的变异大于群体间的变异,遗传变异绝大部分来自群体内部,群体间无显著遗传分化(FST<0.05),平均基因流(Nm)表明小眼薄鳅各采样点群体间基因交流十分频繁。基于Network网络结构可将小眼薄鳅样本划分成3个谱系,谱系间显示了显著的遗传分化(FST>0.25),提示小眼薄鳅种群内部可能有隔离的产生。核苷酸错配分布及Tajima’s D中性检验结果显示小眼薄鳅可能未发生种群扩张事件。
 

关键词: 演化历史, 硅藻功能群, 湖泊生态, 表层沉积物, 空间分布

Abstract: Leptobotia microphthalma is a small freshwater fish, endemic to the Upper Yangtze River, and its distribution is limited. In this study, mitochondrial DNA cytochrome b (cyt-b) and control region sequences were used to investigate the genetic diversity and structure of L. microphthalma populations. A total of 108 fishes were collected from Yibin and Jiangjin stations in the upper Yangtze River. In spite of limited distribution, the population exhibited a high level of genetic diversity; the average haplotype diversity (Hd) and average nucleotide diversity (Pi) were 0.889 and 0.00382 in cyt b and 0.958 and 0.00420 in control region, respectively. Hierarchical analysis of molecular variance (AMOVA) showed no significant genetic differentiation among sampled populations (FST<0.05). The high average gene flow (Nm) value revealed frequent genetic exchange between populations. Three haplotype groups with distinguishing mutant steps were identified from network diagram, and great genetic differentiation (FST>0.25) existed among them, suggesting genetic divergence within population. Nucleotide mismatch distribution and the neutral test (Tajima’s D) result showed that there probably existed no population expansion of L. microphthalma in history.

Key words: lake ecosystem, modern surface sediment, diatom functional group, evolutionary history., spatial distribution