646个人类线粒体rRNA基因序列的多态频率和变异特征对糖尿病、痴呆、心肌病发生风险评估的意义

Significance of the evaluation of characterization of mitochondrial transfer RNA genes polymorphic frequency and variations on the pathogenetic risk of diabetes mellitus, dementia and cardiomyopathy in 646 human sequences

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。

AIM:To explore the polymorphic frequency and variation types of mitochondrial tRNA gene in human mitochondrial sequences. METHODS:The 646 sequences of human mtDNA tRNA genes from GenBank were collected and compared with the revised Cambridge reference sequences. RESULTS: Totally 513 variations in 107 positions of 22 tRNA genes had been found, the mean variation density was 0.052 variations in 100 bases per person.The dominant type of variation was transition(94.17%), followed by transversion(2.53%).The most common transition types were A→G and T→C. The number of tRNALeu was the most at np15 888-15 953, and polymorphic variations were found at 15 positions of 66 nucleotides, variations rate was about 22.72%and significantly higher than that of other 21 tRNA genes.High frequency of polymorphism can be observed in the mitochondrial tRNA genes. The evaluation of variation frequency in these genes provides a good reference for other studies aiming at the relationship of mitochondrial DNA polymorphism with