中文摘要：

测定了长江支流贵定与干流合江和宜都3个群体57尾中华倒刺鲃细胞色素b基因5＇端971 bp序列以分析其遗传多样性和种群结构。结果发现21个变异位点和13个简约信息位点,检测到14种单倍型,平均单倍型多样性（Hd）和核苷酸多样性（Pi）分别为0.7820和0.0025,表现出较低的遗传多样性。合江群体核苷酸多样性最高（0.0036）,宜都其次,贵定最低。在NJ系统树上没有出现明显的谱系结构和地理聚群,AMOVA分析显示遗传变异主要集中在群体内的个体间（61.16%）。宜都和合江群体间的Fst和Nm值分别为0.0974和4.6329,但贵定群体与合江和宜都群体间的Fst值分别为0.4549、0.4875,Nm值分别为0.5991、0.5256,表明长江干流2个地理群体间遗传分化程度低,可视为一个大的随机交配群体;而支流群体没有遗传变异,且与长江干流群体间出现高度分化,可能是由贵定特殊地理条件使基因交流受阻所致。中性检测表明,宜都群体在约为7.6万-3.0万年前的更新世晚期发生过种群的快速扩张。

英文摘要：

The genetic diversity and population genetic structure of Spinibarbus sinensis were examined by sequence analysis of a 971 bp fragment of the 5＇-end of the cytochrome b gene in 57 fish collected from tributary Guiding population and mainstream Hejiang and Yidu populations in the Yangtze River drainage.Totally 21 variable sites and 13 parsimony informative sites were found in 14 haplotypes,and the average haplotype diversity（Hd） and nucleotide diversity（Pi） were 0.7820 and 0.0025 respectively,indicating a poor genetic diversity.The highest nucleotide diversity were found in Hejiang population（0.0036）,followed by Yidu population（0.0025）,and Guiding population had no genetic variation.No obvious lineages and geographic clusters were found in the Neighbor-joining tree,and 61.16% genetic variation occurred within populations in AMOVA analysis.As Fst and Nm between Hejiang and Yidu populations were 0.0974 and 4.6329 respectively,while the Fst and Nm between Guiding population and Hejiang and Yidu populations were 0.4549 and 0.4875,0.5991 and 0.5256 respectively,indicating that genetic differentiation between the two mainstream populations were low,and they could be treated as a single panmictic population.No genetic variation and highly differentiated tributary population might due to the failure to gene flow caused by its special geographical conditions.Neutral analysis suggested that Yidu population had a late Pleistocene rapid population expansion at about.