Gene of the Australian native testifies to two waves of settling of East Asia

Fig. 1. Two waves of settling Asia reconstructed on the basis of comparison genome of the radical Australian (ABR) with genomes of inhabitants of Africa (YRI), East Asia (HAN) and the Central Europe (CEU). Brown colour the first wave ( 75-62 thousand years ago), black — the second ( 38-25 thousand years), by small arrows — an exchange of genes between representatives of two waves is shown. A dashed line — penetration «denisovtsami» genes in a genofund of representatives of the first wave of migrants. Drawing from discussed article in Science  

The analysis genome the Australian native has shown that radical Australians, and also mountaineers of New Guinea occur from an ancient wave of migrants, penetrating to South East Asia 75-62 thousand years ago and crossed with «people from Denisovoj of a cave». Modern Asians occur basically from the second, later wave of immigrants from the West which have separated from ancestors of modern Europeans and have occupied Asia about 38-25 thousand years ago, having forced out and partially having assimilated the predecessors.

Judging by the archaeological data, Australia and New Guinea have been populated with people of modern type already very much for a long time — approximately 50 000 years ago . Moreover, archeological finds on which this conclusion is based, are almost the most ancient indisputable certificates of presence Homo sapiens outside of Africa and the Near East (see: the Analysis mitochondrial DNA has confirmed an ancient origin and long isolation of radical Australians, "Elements", 25.09.2006).

If East Asia has been populated with people of modern type once («a hypothesis of a unique migratory wave») on a family tree of human populations the branch corresponding to the Australian natives, should separate from the East Asian populations already after their branch from ancestors of Europeans (fig. 2, at the left).

Fig. 1. Two waves of settling Asia reconstructed on the basis of comparison genom of the radical Australian (ABR) with genomes of inhabitants of Africa (YRI), East Asia (HAN) and the Central Europe (CEU). Brown colour the first wave ( 75-62 thousand years ago), black — the second ( 38-25 thousand years), by small arrows — an exchange of genes between representatives of two waves is shown. A dashed line — penetration «Denisovsky» genes in a genofund of representatives of the first wave of migrants. Drawing from discussed article in Science  

However the comparative analysis European and Asian genomes has shown that ancestors of modern Asians have separated from ancestors of modern Europeans much later, than Australia has been occupied. It forces to assume that was at least two big waves of settling of East Asia, and those people who have appeared in Australia 50 000 years ago , were representatives of the first wave, and modern Asians occur basically from the second (fig. 2, on the right). Thus there is opened a question on , whether are modern natives lineal descendants ancient settler Australia or, maybe, they occur from later migrants — representatives of the second wave.

To clear up this question, it was necessary to read full a gene at least one radical Australian. It managed to be made to the big international command of the scientists which have informed on the achievement on a site of magazine Science.

DNA for the analysis have taken the  aboriginal of southwest Australia from a scrap of hair (it is powerful 0,6). The sample has been received by known anthropologist Alfredom Heddonom (Alfred Cort Haddon) in 1923 . Interest to this old sample is connected by that in genes of modern radical Australians too considerable European impurity are found out. It complicates reconstruction population stories. However in the XX -th century beginning in southwest Australia Europeans was more few, and authors have counted that DNA from this sample will appear free from European "pollution".

Hopes have justified: any European impurity in read genome it was revealed not. Numerous tests have confirmed that the gene of the Australian had turned out "pure enough" (no more than 0,5 % of impurity of extraneous human DNA) though this bunch of hair and has visited earlier hands of several researchers of the European origin.

Authors have revealed in genom the Australian 449 115 authentic single nucleotide differences («SNPs», see: single nucleotide polymorphism) from "typical" human genome from which 28 395 (6,3 %) have appeared unique (have not been registered at other investigated people).

The Australian have compared on a set SNPs to 1220 individuals from 79 populations. Having applied a  method of the main things a component, authors have established (fig. 3) that from among these 1220 people the nearest relatives of the Australian are mountaineers of New Guinea and inhabitants of island Bougainville (Melanesia, islands Solomonovy). Hardly the Philippine hunters-collectors from a nationality eta) in which occasion anthropologists assumed for a long time have appeared farther relatives that it is the relic people — descendants of an ancient wave of migrants to East Asia.

  Fig. 1. Two waves of settling Asia reconstructed on the basis of comparison genom of the radical Australian (ABR) with genome of inhabitants of Africa (YRI), East Asia (HAN) and the Central Europe (CEU). Brown colour the first wave ( 75-62 thousand years ago), black — the second ( 38-25 thousand years), by small arrows — an exchange of genes between representatives of two waves is shown. A dashed line — penetration «denisovtsami» genes in a genofund of representatives of the first wave of migrants. Drawing from discussed article in Science

By means of difficult statistical tests authors have shown that genomes the data corresponds to a hypothesis about two waves of settling of East Asia is better (and radical Australians and Melanesians are descendants of an ancient wave), than to the assumption of a unique wave of migrants. Between representatives of these two waves there was an exchange of genes, therefore Australians and melanesians genetically all the same are closer to Asians, than to Europeans. All of them are equally far from Africans. Authors have calculated that ancestors of Australians should separate from ancestors of Europeans and Asians about 75-62 thousand years ago, and last two groups of populations "have dispersed" about 38-25 thousand years ago (that coincides with the estimations received by earlier other researchers). Thus, the scheme shown on fig. 2 on the right proves to be true.

Authors have found out that an impurity of Neanderthal genes in genome the Australian same, as at Europeans and Asians (see: by the Gene of Neanderthal men it is read: Neanderthal men have left a trace in genes of modern people, "Elements", 10.05.2010). It means that the sapienses who have left Africa, most likely, have received this impurity still before ancestors of Australians have separated from ancestors of Asians and Europeans (that is earlier, than 75-62 thousand years ago). It was found out also that an impurity «denisovtsami» genes (see: It is read nuclear by a gene of the person from Denisovoj of a cave, "Elements", 23.12.2010) in genome the Australian much more, than at Europeans and Asians, and it is comparable to that at new Guinean mountaineers.

Thus, research has shown that sapienses occupied East Asia, most likely, two waves. Representatives of the first wave were crossed with denisovtsami and very much have early got into Australia. Representatives of the second wave have forced out (and partially assimilated) the predecessors which lineal descendants have remained only in Australia and mountain areas of New Guinea. The nationality Aeta from the Philippine islands, probably, is one more relict of the first wave of migrants.

Source: Morten Rasmussen, Xiaosen Guo, Yong Wang, Kirk E. Lohmueller, Simon Rasmussen, Anders Albrechtsen, Line Skotte, Stinus Lindgreen, Mait Metspalu, Thibaut Jombart, Toomas Kivisild, Weiwei Zhai, Anders Eriksson, Andrea Manica, Ludovic Orlando, Francisco De La Vega, Silvana Tridico, Ene Metspalu, Kasper Nielsen, María C. Ávila-Arcos, J. Víctor Moreno-Mayar, Craig Muller, Joe Dortch, M. Thomas P. Gilbert, Ole Lund, Agata Wesolowska, Monika Karmin, Lucy A. Weinert, Bo Wang, Jun Li, Shuaishuai Tai, Fei Xiao, Tsunehiko Hanihara, George van Driem, Aashish R. Jha, François-Xavier Ricaut, Peter de Knijff, Andrea B Migliano, Irene Gallego-Romero, Karsten Kristiansen, David M. Lambert, Søren Brunak, Peter Forster, Bernd Brinkmann, Olaf Nehlich, Michael Bunce, Michael Richards, Ramneek Gupta, Carlos D. Bustamante, Anders Krogh, Robert A. Foley, Marta M. Lahr, Francois Balloux, Thomas Sicheritz-Pontén, Richard Villems, Rasmus Nielsen, Wang Jun, Eske Willerslev. An Aboriginal Australian Genome Reveals Separate Human Dispersals into Asia //Science. Published online 22 September 2011.