西藏藏族mtDNA COⅡ/tRNA^(Lys)基因间区9-bp缺失多态性

Polymorphism of deletion of mtDNA intergenic COⅡ/tRNA^(Lys) among Tibetans

目的通过对西藏拉萨和那曲两地区藏族群体线粒体DNA COⅡ/tRNALys基因间(Ⅴ区)的研究,了解Ⅴ区9-bp短串联重复序列的多态性。方法应用PCR法扩增163例(拉萨82例,那曲81例)藏族青少年标本后琼脂糖凝胶电泳进行检测,并对突变样本测序分析。结果共有9例缺失型(占5.52%),其中拉萨藏族中有4例(4.88%),那曲藏族中有5例(6.17%),其余为标准型,未发现3型和长型多态。结论研究结果表明西藏两地区藏族人群中只存在mtDNAⅤ区的标准型和缺失型两种多态性,而且其缺失率经两样本率的χ2检验证明差别不大。

Objective To investigate the polymorphism of mtDNA region V among Tibetans in Tibet, China.Methods All the 163 Tibetans＇ （82 in Lhasa and 81 in Nagqu） DNA fragments in mtDNA intergenic COⅡ/tRNA^Lys were amplified by PCR technique. Some 9 bp deletion samples were analysed by direct sequencing of PCR praducts.Results Among the 163 Tibetans screened, only two types of polymorphism （normal and deletion） were found. The frequency of the 9 - bp deletion was 5.52% （9/169） ; the frequencies in Lhasa and Nagqu Tibetans were 4.88% （4/82） and 6.17% （5/81）, respectively. All the deletive cases identified in this region lack one of two adjacent copies of a 9 - bp sequence nonnaUy. Conclusions 9 - bp deletion was discovered in Tibetans of Lhasa and Nagqn, whose frequency is similar,