中文摘要：

测定了长江水系贵定和乐山2个群体30尾泉水鱼细胞色素b基因1 026 bp序列,发现13个变异位点,检测出7种单倍型,Hd和Pi分别为0.772和0.0041,其中贵定和乐山群体的Hd分别为0.695和0.362,Pi分别为0.0030和0.0004,呈现出单倍型多样性较低和核苷酸多样性极低的特点;两个群体间的Fst和Nm值分别为0.7417和0.17,AMOVA分析显示遗传变异主要集中在群体间（74.17%）,表明群体间出现高度的遗传分化;在邻接树上出现两个按地理来源聚群谱系,呈现出明显的地理结构;估算群体间分歧时间大约在16万年前,为更新世时期。中性检测表明两个群体在过去没有发生种群的快速扩张。建议将贵定和乐山群体作为不同的管理保护单位加以保护。

英文摘要：

Abstract： 1 026 bp sequences of mitochondrial DNA cytochrome b gene of 30 individuals from 2 populations of Pseudogrincheilus procheiluys collected in Guiding and Leshan from the Yangtze River drainage respectively were sequenced, totally 13 variable sites were found in 7 baplotypes, the global haplotype diversity （Hd） and nucleotide diversity was 0.772 and 0.0041 respectively, the haplotype diverisity in Guiding and Leshan populations were 0.695 and 0.362 respectively, their nueleotidc diversity were 0.0030 and 0.0004 respectively, indicating a pattern of low haplotype diversity and very low nucleotide diversity. Fst and Nm values between the two populations were 0.7417 and 0.17 respectively, and 74.17% genetic variation occurred between populations in AMOVA analysis, suggesting they were highly differentiated. Obvious geographic structure were revealed by 2 lineages coincided with geographic clusters formed in the Neighbor-joining tree, and the estimated divergence time were about 160 000 years ago, i.e., in the Holocene. No rapid expanding was found by using the neutrality tests, and the two populations from the Yangtze River should be protected as two different management units.