The genetic diversity and population history of indigenous peoples in Asia

要旨

"    Asia is home to many diverse human populauons and has been of much interest to anthropologists and geneticists alike. The focus of thiS thesis is the genetic diversity and migration histories of indigenous populations from southeast Asia atld the Japanese Archipelago. Based on archae010gical and linguistic data, the origins of southeast Asiatls can be traced back to two major migrations; the ancient 'out of Africa' migration circa 50,ooo years befoN present (YBP) and the relatively recent 'out of Taiwan' expansion of agriculturalists who speak Austronesia languages, approximately 5,00O YBR hl Malaysia and the Philippines, there are indigenous groups ca11ed Negritos whose physical appearance is distinct from their neighboring Populations and are thought have originated from the 'out of Africa' migration. The majority Of other southeast Asian groups are thought to have originated from the 'out of Taiwan' migration. As for the peopling of the Japanese archipelago, it is characterized by two important Periods: the Jomon period from 15, ooo t0 3,00O YBP; and the Yayoi period from 3, ooo t0 1,700 YBP. According to the dual-structure model, the current Japanese population was the result of admixture between Jomon populations who originated from Southeast Asia and the incoming 'Yayoi migrants from mainland Asia. some minority groups in Hokkaido and the Ryukyu islands maybe direct descendants of the Jomon peoples.    By analyzing approximately 50,ooo genome-wide sNp data generated by me and other Pan-Asian sNp consortium (PASNP) members,1investigated the genetic structure that may exist within indigenous groups of Malaysia and elucidated their relationship with other southeast Asians. using principal component A11alysis (PCA) and structure analysis,1 found traces Of recent and sustained admixture within the Negrito, Indian and Austronesian (Temuan, Bidayuh, Melay) groups. comparisons with other southeast Asians revealed that the Malaysian Negrito appeared to be distinct from the Philippine Negritos on the pcA plot. A closer look at the relationship between Austronesian populations revealed genetic substructure which mirrors geographical affinities, which may be explained by geographical isolation f0110wing the 'out of Taiwan' expansion or alliteratively there may be separate population movements involving other Austronesian groups.1hese observations demonstrate the impact of admixture on the genetic Substructure of indigenous southeast Asian groups and hints at more complex migration history Of the Negritos and AustronesianS than the simple 'out of Africa' a11d 'out of Taiwan' models Would suggest.    Next l conducted a11analysis of complete mitochondrial DNA (mtDNA) sequences to test the plausibility, impact and timing of the migration models in indgenous Malaysian Populations.1 generated complete mtDNA sequences in 86 individuals from four indigenous Malaysian groups. In the Jehai(Negrito), one of the frequent haplogoups was R21 Which is indigenous to west Malaysia and dates back to the Pleistocene (~40,00O YBP). The three Austronesian groups (Bidayuh, selatar and Temuan) showed high frequencies of haplogroups N9a6, N9a6a, Fla'C, N21 and N22 Which have mainland Asian origins around 30,ooo t0 10,000 11 YBP. Haplogoups associated with the 'out of Taiwan' expansion were either found at very low frequencies or not detected at a11 in those three Austronesian groups. principal component Analysis distinguishes the Malaysian Negritos from the Austronesians and also shows a dichotomy between Austronesians from Sumatra and Java and those from Taiwa11 and Philippines. As with the sNp analysis, results from mt DNA showed no apparent link between the Negritos of west Malaysia and those from Andaman and Philippines. Regarding the origin of Austronesians, our results show support for ‘eagerly train' migration originating from Indochina Or south china around 30,ooo t0 10,00O YBp which predates but does not rule out

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