中文摘要：

对扁吻鱼（Aspiorhynchus laticeps）和塔里木裂腹鱼（Schizothoraxbiddulphi）细胞色素c氧化酶亚基（COI）基因片段进行扩增。通过序列测定得到624bp的基因片段,无碱基的插入和缺失,A、T、G、C碱基中G含量最低,A＋T含量高于G＋C含量,与其它鱼类COI基因片段研究结果相一致。2个种间共检测到38处核苷酸替换,其中35处碱基转换,3处碱基颠换,蛋白质编码基因上的核苷酸替代主要是密码子第3位点上的同义替换。在编码的208个氨基酸中,仅发生2处氨基酸替代,替代率为0.96%。采用Kimura-2法计算种间平均遗传距离为0.06,以鲤作外群构建NJ系统树,扁吻鱼和塔里木裂腹鱼亲缘关系较近,而与新疆裸重唇鱼、斑重唇鱼亲缘关系较远。

英文摘要：

Mitochondrial cytochrome oxidase subunit I（COI）fragments of Aspiorhynchus laticeps and Schizothorax biddulphi were amplified.By sequencing,the sequence of 624 bp nucleotide was obtained,and no insertion/deletion was observed.Base G content was the lowest of all,and the content of A＋T was higher than that of G＋C,which was similar to the results in other fishes.38 nucleotide substitutions were checked between the two species which included 35 transitions and 3 transversions,and most of them were synonymous transitions at the third codon positions in the protein-coding genes.There were only two amino acid substitution in encoded 208 amino acids,and the substitution ratio was 0.96%.The average genetic distance by Kimura-2 method between A.laticeps and S.biddulphi was 0.06.Cyprinus cyprio was chosen as an out-group,and the NJ clustering tree indicated that A.laticeps and S.biddulphi had the closest relationship.