DISPERSAL OF MODERN HUMANS INFERRED FROM MITOCHONDRIAL DNA POLYMORPHISMS

分析了泰国人(清迈和坤健的泰国人，以及原住民Sakai人)、马来人和印尼人等5个东南亚人群的线粒体DNA主要非编码区(D-loop)的核苷酸序列。基于对159个东南亚人的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个是各自种群独有的，而8个是两个或三个种群共享的。在共有的类型中，泰国人和印尼人之间发现了6个共同的类型。除Sakai外，其余东南亚人群均存在COII/tRNA(Lys)9碱基对缺失，频率不一。D-loop序列的变异表明，缺失事件在东南亚人的祖先中只发生过一次。系统发育分析表明，尽管不同种群的谱系在系统发育树中完全混杂在一起，但东南亚的谱系至少被划分为六个单系簇。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、非洲人和美洲人在内的整个人类群体的系统发育分析表明，泰国人(清迈和坤健)和印度尼西亚人之间的遗传亲缘关系最近。此外，种群之间的净核苷酸多样性表明，整个亚洲人可以分为南方和北方两个群体。因此，这项研究的结果表明，亚洲邻近地区之间的移民事件过去经常发生。

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.