|Budget Amount *help
¥8,100,000 (Direct Cost : ¥8,100,000)
Fiscal Year 1998 : ¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1997 : ¥4,600,000 (Direct Cost : ¥4,600,000)
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.