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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。
Small loach loach is a unique small fish in the upper reaches of the Yangtze River, the natural distribution of narrow. In this study, 108 samples of Leptobotia microphthalma collected from Jiangjin section of the upper reaches of the Yangtze River and Yibin section of the lower Minjiang River were analyzed for their genetic diversity and inheritance using the sequences of mitochondrial cytochrome b (cytb) The structure was analyzed. The results showed that 28 polymorphic loci and 34 haplotypes were detected in the cytb sequence of B. opiatella. The average haplotype diversity index (Hd) and nucleotide diversity index (Pi) were 0.889 And 0.00382, respectively. There were 49 mutation sites and 65 haplotypes in the control region sequence. The Hd index and Pi index were 0.958 and 0.00420, respectively. The analysis of molecular variance (AMOVA) showed that the variation in the sampling point population of Misgurnus angustifolia was larger than that among the populations. Most of the genetic variation came from the inside of the population with no significant genetic differentiation (F_ (ST) <0.05) The flow (Nm) indicates that the gene exchange among the sampled populations of M. oputa was very frequent. Based on the network structure of Network, the Loach can be divided into three genera, and the genetic differentiation (FST> 0.25) was shown among the pedigree, suggesting that there might be segregation within the population of Loach. Nucleotide mismatch distribution and Tajima’s D neutral test showed that P. euchromai may not have population expansion events.