中国民族人群线粒体DNA 9bp序列缺失的分布

采用PCR-PAGE方法,对16个少数民族群体和9个地区的汉族群体共1521人进行了线粒体基因组COⅡ和tRNAlys基因间非编码序列中串联重复的9bp序列缺失情况的检测.贵州苗族、布依族的缺失频率在所研究的民族人群中最高,分别达到32.4%和30.8%,云南佤族、拉祜族和新疆维吾尔族、蒙古族频率相当低(≤4%),新疆哈萨克族群体中未检测到缺失类型,而其他群体的频率表现为中等或较低(6%～24%).除新疆汉族、贵州汉族和报道的台湾汉族外,其他各地汉族群体间缺失频率差异不大;有些来自同一地区或共同历史起源的民族群体的缺失频率没有表现出相近的分布趋势.总体上南方的、沿海的民族群体比北方的、内地的群体表现出较高的缺失频率.综合统计已报道的和此次研究的中国人群的9bp缺失频率约为17.20%.另外,还在4个个体中检测到并经测序证实存在9bp的3个重复;在随机抽样选择测定的有缺失和没有缺失的27个个体中,仅在1例中发现有报道的X.Ⅱ型9bp模式.     

Frequency of the mtDNA 9-bp deletion in Chinese ethnic groups

The 9-bp deletion in the COIl/tRNALys intergenic region (region V) of human mitochondrial DNA was screened in 1521 Chinese from 16 ethnic groups and 9 Han geographic groups. The highest frequency was found in populations of Miao (32.4%) and Bouyei (30.8%) from Guizhou Province, whereas no deletion was found in Kazak population in Xinjiang. In the populations of Wa and Lahu from Yunnan Province, Uygur and Mongolian from Xinjiang,the deletion frequency was relatively low ( ≤ 4 % ), while in the remaining 18 groups, the frequency was moderate (6 % ～ 24% ). Except those Hans in Xinjiang, Guizhou and that reported in Taiwan, the deletion frequency in the Han geo graphic groups did not show a substantial difference. However, the deletion frequency in some ethnic groups from the same geographic region or with similar ethnohistory did not show similarity. A general decrease tendency in the deletion frequency was found from south to north and from coastal to inland. The frequency of the 9-bp deletion was approximate ly 17.20% in all Chinese we studied and reported elsewhere. Additionally, 4 individuals were found to carry the tripli cation of 9-bp segment in region V; one individual had X. II type of 9-bp deletion; and no other length polymorphisms were detected in this region in 27 randomly selected individuals with or without the deletion.