2种珍稀裂腹鱼类线粒体DNA部分序列片段的比较分析

对扁吻鱼(Aspiorhynchus laticeps)及塔里木裂腹鱼(Schizothorax biddulphi)线粒体CO I(624 bp)、Cyt b(712 bp)和D-loop(457 bp)基因片段进行了PCR扩增和序列测定.通过分析比较发现,3个片段A+T含量与其他鱼类相比均较高,G含量偏低这一现象在...

Comparative Analysis of mtDNA Gene between Two Rare Schizothoracine Fishes

The mtDNA COⅠ(624 bp),Cyt b(712 bp) and D-loop(457 bp) gene fragments of Aspiorhynchus laticeps and Schizothorax biddulphi were sequenced by PCR respectively and sequence comparisons were made to identify differentiation.The percentage of A+T content was higher than that of G+C content in three gene fragments.There was a strong bias against G content,especially in the third codon positions of protein-coding genes(COⅠ and Cyt b).Sequence analysis indicated that the variation of intra-species was low and the nucleotide substitution rate of three gene fragments arranged from high to low was D-loop>Cyt b>COⅠ.The estimated divergence time between two Schizothoracine species based on Cyt b gene was about 3.57 MaBP in Pliocene,which was earlier than the specialized grade and high specialized grade species.Because the Tarim River lies in the northern edge of the Qinghai-Tibet Plateau and is geographical development as a part of the Tibetan Plateau,the uplift of Qinghai-Tibet Plateau influences the evolution of Schizothoracine species in Xinjiang to some extent.