Ancestors of the Aborigines left Africa first

First sequencing of an aboriginal genome speaks for several migration waves of Homo sapiens

This reconstruction of the migration of modern humans from Africa shows that the ancestors of the aboriginal people (red, ABR) already left Africa before Europeans (CEU) and Asians (HAN) parted ways in their migration. © Science / AAAS
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The ancestors of the Australian Aboriginals left Africa at least 24, 000 years before the ancestors of Europeans and Asians. Researchers now conclude that this is the first sequencing of the genome of an Australian Aborigine. The comparison with the genes of Asians, Africans and Europeans shows that the first Aborigine ancestors emigrated from Africa already 62, 000 to 75, 000 years ago, reports the international team of scientists in the journal "Science". Modern Asians, on the other hand, came from early humans, who came to Asia only 25 to 38, 000 years ago.

The Australian aborigines are considered one of the oldest peoples of modern humanity. Archaeological finds prove that they lived in Australia around 50, 000 years ago - long before Homo sapiens took root in Europe. "The genetic history of Aborigines is therefore very important for understanding the evolution of modern humans, " the researchers write. So far, it has been controversial how the ancestors of the Aborigines once came from Africa to Australia. "According to previous theory, East Asia is said to have been colonized by a single early wave of migration, " say Willerslev and his colleagues. The Aborigines would split off from these first Asians at a later date.

The comparison with 79 genome sequences of Africans, Europeans and Asians shows, however, that the ancestors of the Aborigines have already separated from the common ancestors of Eurasier. Only then was the separation of Europeans and Asians, the scientists report. The Australian aborigines are therefore today one of the few peoples, which went back to the earliest human emigrants from Africa.

This bundle of tufts from an Aboriginal woman living around a hundred years ago provided the DNA for the first genome sequencing of an Australian aborigine. © Science / AAAS (Mikal Schlosser)

Haarlocke from young West Australians supplied the DNA

The hair shark that supplied the DNA came from a young Aboriginal who lived in Western Australia at the beginning of the 20th century. He is said to have donated the lock of hair to a British anthropologist who was then in this region. The hair was not frozen, but was kept in the museum for about one hundred years under normal conditions.

Thanks to state-of-the-art sequencing technology, however, it was still possible to sequence the DNA of the nucleus and the mitochondrial DNA. "In this way, genetics provides a unique contribution to our understanding of how and when humans invaded the world, " says Francois Balloux of Imperial College, London, head of the geneticist team in London. display

First pioneers of humanity

"While the ancestors of the Europeans and Asians still roam around somewhere in Africa or the Middle East, Aboriginal ancestors spread quickly, " says study leader Eske Willerslev of the University of Copenhagen. They were the first modern humans to migrate over unknown territory to Asia and finally crossed the sea to Australia. The now sequenced Aboriginal DNA proves that it was derived from these first human pioneers and discoverers.

According to the researchers, the early migration of Aboriginal ancestors also speaks against the common theory of just one major wave of Homo sapiens emigration from Africa. "Such a model is not compatible with our genetic data, " say the scientists. The results speak instead for several waves of emigration. After this, the original Aboriginal people left Africa, followed by the later Europeans and Asians. There are also initial indications of two more waves of migration between these events, the researchers say. (Science, 2011; DOI: 10.1126 / science.1211177)

(Science, dapd, 23.09.2011 - NPO)