剑尾鱼线粒体DNA D-环及侧翼tRNA^(thr)和tRNA^(pro)序列与结构分析

Sequence and structure analysis of mitochondrial D-loop and tRNA^(thr) & tRNA^(pro) genes in Xiphophorus helleri

采用PCR方法从剑尾鱼(Xiphophorushelleri)线粒体基因组中扩增到1段约15.5kb的片段,测定了其中627个碱基的序列。经测序分析表明,该扩增片段包括486bp的D 环的部分序列以及D 环5'端的tRNAthr和tRNApro基因的完整序列。其中486bpD环序列包含3段保守的终止相关序列TAS、与TAS互补的序列以及类似其他鱼类线粒体CSB序列。tRNAthr由线粒体DNA的H链编码,长度为72bp。tRNApro由线粒体DNA的L链编码,长度为69bp。并绘制了这2种tRNA的二级结构图。本研究所测定的基因序列已登录国际GenBank数据库,序号为AF489918。

The swordtail fish Xiphophorus helleri were used as the experimental animal, which were the inbred strains of 19th generation cultivated in the laboratory. Twenty mg of liver tissue was collected to prepare the total DNA. In order to learn the molecular background of the fish and build molecular markers for its different strains, a 15.5 kb fragment of swordtail fish mitochondrial DNA was obtained by PCR method and a 627 bp sequence was determined, and by sequence analysis, the results showed this sequence contained 486 bp of D-loop sequence and complete tRNAthr and tRNApro genes. The tRNAthr contained 72 bp and was coded by H chain of mitochondrial DNA. The tRNApro contained 69 bp, coded by L chain. The characteristics of D-loop sequence and the second structures of the two tRNA were described and analyzed. The gene sequences obtained in this study have been recorded in the GenBank, whose number is AF489918.