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目的:探讨人类线粒体tRNA基因序列的多态频率和变异类型。方法:搜集基因文库记录的646个人类线粒体tRNA基因序列,并与修正的剑桥序列进行比对分析。结果:在22个线粒体tRNA基因序列中共发现107个位点共具有513个碱基变异,平均变异密度约为每人每100碱基0.052个变异。可变碱基的主要变异形式为碱基转换(94.17%),其次为颠换(2.53%),最常见的碱基转换类型为A→G和T→C。位于np15888～15953的tRNA苏氨酸基因变异位点数最多,在该基因中66个核苷酸中有15个位点具有多态性碱基替换变异,约占该基因22.72%,明显高于其他21个tR-NA基因。结论:线粒体tRNA基因具有高频多态变异,其变异频率的确定可为针对线粒体基因多态性与糖尿病、痴呆、心肌病相关疾病发生风险评估的其他研究提供参考。
Objective: To investigate the polymorphic frequency and variation types of human mitochondrial tRNA gene sequences. Methods: 646 human mitochondrial tRNA gene sequences were collected from the gene library and compared with the modified Cambridge sequences. RESULTS: Of the 22 mitochondrial tRNA gene sequences, a total of 107 base loci were found to have 513 base pairs with an average mutation density of 0.052 per 100 base pairs. The main variation forms of variable bases are base conversion (94.17%), followed by transversion (2.53%). The most common types of base conversion are A → G and T → C. The number of tRNA threonine genes located at np15888 ~ 15953 was the largest, 15 of 66 nucleotides had polymorphic base substitution mutation, accounting for 22.72% of the 66 genes, which was significantly higher than other 21 tR-NA genes. CONCLUSION: The mitochondrial tRNA gene has high frequency polymorphism. The frequency of mitochondrial tRNA gene mutation can be used as a reference for other studies on risk assessment of mitochondrial DNA polymorphism and diabetes, dementia and cardiomyopathy-related diseases.