DISPERSAL OF MODERN HUMANS INFERRED FROM MITOCHONDRIAL DNA POLYMORPHISMS

分析了5个东南亚人群（包括泰国人（来自清迈和孔敬的泰国人，以及原住民酒井人）、马来人和马来西亚人）线粒体DNA主要非编码区（D环）的核苷酸序列。基于对159名东南亚人的482个碱基对序列的比较，观察到106种不同的序列类型。其中，98个是其各自种群所特有的，而8个是两个或三个种群所共有的。在共有的类型中，泰国人和泰国人共有六种。基因间COII/tRNA（赖氨酸）9碱基对缺失，观察到在每个东南亚人口除了酒井不同的频率。D环序列变异表明，在东南亚人的祖先中，缺失事件只发生过一次。系统发育分析表明，东南亚血统被归类为至少6个单系簇，虽然血统从不同的人口是完全混杂在系统发育树。对包括东亚人（中国人、韩国人、日本大陆人、琉球人和阿伊努人）、欧洲人、非洲人和美洲印第安人在内的整个人类群体的系统发育分析显示，泰国（清迈和孔敬）和印度尼西亚两个群体之间的遗传亲和力最接近。此外，人群之间的净核苷酸多样性表明，整体亚洲人可以分为南方和北方组。因此，这项研究的结果表明，亚洲相邻地区之间的迁移事件在过去是频繁的。

Nucleotide sequences of the major noncoding (D-loop) region of human mitochondrial DNA from five Southeast Asian populations including Thais (Thais from Chiang Mai and Khon Kaen, and aboriginal Sakai), Malays and Indonesians were analyzed. Based on a comparison of 482 base pair sequences in 159 Southeast Asians, 106 different sequence types were observed. Of these, 98 were unique to their respective populations, whereas eight were shared between two or three populations. Among the shared types, six were found in common between the Thais and Indonesians. The intergenic COII/tRNA(Lys) 9 base pair deletion was observed in every Southeast Asian population except Sakai with varying frequencies. The D-loop sequence variation suggests that the deletion event occurred only once in the ancestry of Southeast Asians. Phylogenetic analysis revealed that Southeast Asian lineages were classified into at least six monophyletic clusters, though lineages from different populations were completely intermingled in the phylogenetic tree. Phylogenetic analysis of the entire human population including East Asians (Chinese, Koreans, mainland Japanese, Ryukyuans and Ainu), Europeans, Africans, and Amerinds revealed the closest genetic affinity among the two Thai (Chiang Mai and Khon Kaen) and Indonesian populations. Furthermore, net nucleotide diversity between populations suggest that overall Asians can be separated into southern and northern groups. Thus, the results of this study suggest that migration events between adjacent areas of Asia were frequent in the past.