长江上游特有鱼类红唇薄鳅线粒体控制区遗传多样性研究

Genetic diversity of Leptobotia rubrilabris in the upper Yangtze River inferred from mitochondrial control region

红唇薄鳅(Leptobotia rubrilabris)是长江上游特有鱼类,近年来资源量不断下降。本研究利用线粒体控制区序列片段(896 bp)分析了长江上游红唇薄鳅的遗传多样性及遗传结构,为其资源保护提供科学依据。共采集了119尾样本,来自长江上游江津、四川南溪、岷江下游蕨溪等。结果显示,共检测到58个单倍型,平均单倍型多样性为0.967,平均核苷酸多样性0.006 7,表明红唇薄鳅种群具有较高的遗传多样性。单倍型NETWORK网络关系图和分析系统树结果显示红唇薄鳅单倍型不按地理分布聚类,但是明显分成了2个谱系,表明红唇薄鳅群体发生了同域遗传分化。AMOVA分析结果显示,采样点和采样时间的群体间没有发生遗传分化。中性检验、错配分析及BSP(Bayesian skyline plot)分析表明红唇薄鳅Lineage 1种群在距今0.007 5~0.055 Ma(百万年)期间发生过种群选择或扩张事件。

Leptobotia rubrilabris is a small freshwater fish, endemic in Upper Yangtze River, and its natural resource was decreased in recent years. In this study, mitochondrial control region sequences（ 896 bp） were used to analysis genetic di-versity and structure of L. rubrilabris population. A total of 119 individuals collected from 3 sites as Jiangjin, Nanxi, Juexi in the Upper Yangtze River were used here. The results showed that 58 haplotypes were identified among sapmles and haplo- type diversity and nucleotide diversity were 0. 967 and 0. 006 7, respetively, indicating moderately high genetic diversity for L. rubrilabris population. Network diagram and phylogenetic NJ tree of haplotype showed that haplotypes were not clus-tered as the geographical samples, but divided into two lineages, which indicated that there was sympatric genetic diver-gence in population of L. rubrilabris. The molecular variance analysis （ AMOVA ） showed that there was no genetic differen-tiation between populations of sampled sites and time. The neutral test , nucleotide mismatch distribution and Bayesian skyline plot （BSP） analysis showed that historical population expansion had occurred in Lineage 1 of L. rubrilabris, and the expansion time was deduced in 0. 007 5 ？0. 055 Ma before.