中文摘要：

采用聚合酶链式反应克隆川陕哲罗鲑Hucho bleekeri线粒体细胞色素b基因（Cyt b）,首次报道该基因的全长序列（1140bp,GenBank登录号FJ597623）,并与鲑亚科中其他5属14个物种的Cyt b基因进行同源性比较,分析了碱基组成和变异情况,以白鲑亚科的白鲑Coregonus lavaretus作为外群构建了ML、NJ和MP系统发育树。遗传距离和分子系统学分析表明,川陕哲罗鲑与细鳞鲑属的细鳞鱼Brachymystax lenok之间的遗传距离相对较小（8.47%）,在系统发育树上两者聚在一起,提示川陕哲罗鲑与细鳞鱼存在较近的亲缘关系,该结果与以往的形态学分类不相符。

英文摘要：

In the present study, the complete sequence of the mitochondrial cytochrome b gene from Hucho bleekeri was amplified and sequenced. A DNA fragment of 1140 bp （ GenBank accession no. FJ597623） was reported for the first time. By comparing with the sequences from fourteen other species representing five genera in subfamily Salmoninae, the base compositions and divergences among these sequences were analyzed. The aligned sequences were subjected to maximum likelihood （ML）, neighbor-joining （NJ） and maximum parsimony （MP） analyses while using Coregonus lavaretus as an outgroup. Molecular phylogenetic analyses showed that Hucho bleekeri and Brachymystax lenok cluster together and there was relatively low （8.47%） genetic distance between them, suggesting that there is a relatively closed relationship between Hu- cho bleekeri and Brach）mystax lenok. The result was not consistent with previous taxonomic studies based on morphological characteristics.