中文摘要：

分析了中国近海连云港、舟山和福州38胜鮸鱼线粒体细胞色素b（Cytb）基因的1140bp序列，共检测到39个变异位点和5个简约信息何点；共有27个单倍型，总的单倍型多样性为0．960±0．020，核苷酸多样性为0．00271±0．00030，表现为高单倍型多样性和低核苷酸多样性；Tajima’S中性榆验为负值且显著（-2．36010，P〈0．05），在简约性网络图中单倍型呈星状分布，核苷酸不配对分析呈单峰曲线，表明中国近海觑鱼经历过种群扩张，推测扩张年代约为8万年前。在邻接树和简约性网络图中不同地理来源的单倍型交错分佰，群体间有较低的FST值（-0．0190～0．0081）和较高的Nm值（-62．53～26．82），分子方差分析（群体间-1．12％）表明群体问未出现明显的遗传分化，可作为一个管理保护单位．推测兢鱼生活史中存在一定规模的洄游以及扩张后的群体尚未在迁移与漂变间达到平衡是未榆测到垃著地理和谱系结构的主要原因。

英文摘要：

Complete sequences of mtDNA Cytochrome b gene （1 140 bp） of 38 individuals of Miichthys miiuy collected in Lianyungang, Zhoushan and Fuzhou along coastal waters of China were analyzed, of which 27 haplotypes were defined by 39 variable ＇sites And 5 parsimony-infiormative sites. The global haplotype diversity （Hd） and nucleotide diversity （Pi） were 0.960±0.020 and 0.00271± 0.00030 resp~＊ctively, which showed high haplotype diversity and low nueleotide diversity. Neutral test of Tajima＇s （-2.36010）, starz-like statistical parsimony cladogram and mismatch distribution revealed a population expansion at about 80 thousand years in Miichthys miiuy. Low genetic differentiated index （Fst=-0.0190-0.0081） and high gene flow （Nm=-62.53-26.82）, intertwined haplotypes of various geographie populations in Neighbor-joining and TCS tree, and analysis of molecular variance （AMOVA, -1.12%） among populations showed no significant population differentiation,and the three populations could be protected as a single management unit, which wereI inconsistent with conventional partitions of geographical population. A eertern degree of migration in the life history and insufficient time to attain a equilibrium ＂after a large range population expansion may be attributed to account for the lack of genet/c structure .