中文摘要：

测定并分析了长江水系14尾中华鳖（Pelodiscus sinensis）的线粒体细胞色素b基因1 140 bp序列,结合GenBank中下载的3个序列,发现了243个变异位点,61个简约信息位点;A＋T含量（60.6%）明显高于G＋C含量（39.4%）;17个中华鳖序列中共存在10个单倍型,单倍型多样性（Hd）为0.882,核苷酸多态性（Pi）为0.01002。在分子系统树上,17个样本共形成3个谱系,其中长江中下游出现遗传距离为0.023的2个谱系,谱系A由7个单倍型（共14尾）组成,谱系C由2个单倍型（共2尾）组成。韩国1尾单独为谱系B,与A、C谱系之间的遗传距离分别为0.030、0.031。推测3个谱系间分化时间约为5百万年,建议分别加以保护。长江中下游不同地理来源的个体混杂分布,没有形成明显的地理聚群,不同群体间的遗传变异大于群体内的遗传变异。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多峰型,表明中华鳖未经历过种群扩张。

英文摘要：

Sequences of Complete mitochondrial DNA Cytochrome b gene of Pelodiscus sinensis in Yangtze River were sequenced and analyzed in present study.Combined with homologous sequences downloaded from GenBank,243 variable sites and 61 parsimony-informatic sites were found in the 1 140 bp sequences,and A＋T content（60.6%） were more higher than G＋C content（39.4%）.Totally there existed 10 haplotypes of 17 samples in Yangtze River,and haplotype diversity（Hd） was 0.882,nucleotide polymorphism（Pi） was 0.01002.In the Neighbor-joining tree 3 lineages were recovered,of which genetic distance between linage A composed of 7 haplotypes from 14 individuals and linage C contained 2 haplotyes from 2 individuals found in the Yangtze River were 0.023,and Lineage C represented by single turtle were from South Korea.and the genetic distance to the two lineages in Yangtze River were 0.030 and 0.031 respectively.The divergence among the three lineages was dated back to about 5 MY.The 3 Evolutionarily Significant Units（ESUs） recognized in present study should be protected respectively.Individuals from different locality in the Yangtze River were interwined without obvious genealogical nor geographic clusters,and genetic variation among different groups is greater than those within populations.The negative and highly significant values in the Fu＇S Fs tests and Tajima＇s D tests of the whole population and multiple peaks appeared in the mismatch distributions indicated that Pelodiscus sinensis have not experienced a population expansion.