A 100-year-old lock of hair is telling scientists a new story of humanity's early migration, indicating that our ancestors moved from Africa to the rest of the world in two separate waves -- one through southern Asia to Australia, the other to Europe.
While these findings reveal Aborigines as one of the oldest continuous populations outside of Africa as well as the population with the longest association with the land on which they live today, they would stir up controversy among scientists by challenging the traditional theory of one single wave of migration out of Africa into Europe.
The hair sample was donated to British anthropologist Alfred Haddon by a young Aboriginal man in 1923, and remained at Cambridge until last year when the study's lead author Eske Willerslev from the University of Copenhagen learned of its existence. He and his team then used the DNA of the ancient hair to sequence the Aboriginal genome for the first time ever.
In comparison with DNA from other humans, the DNA in the Aboriginal genome revealed the paths taken by the Aborigines' ancestors when they first migrated out of Africa as the first group to split away from the main group before Europeans and East Asians split from each other, according to the findings.
The rate of mutation in DNA indicates that the Aborigines moved out of Africa possibly 62,000 to 75,000 years ago toward Australia, and that the ancestors of Europeans and East Asians split from each other around 25,000 to 38,000 years ago.
Aboriginal Australians descend from the first human explorers, said Willerslev, whose work was published in the journal Science Express on Thursday.
While the ancestors of Europeans and Asians were sitting somewhere in Africa or the Middle East, yet to explore their world further, the ancestors of Aboriginal Australians spread rapidly; the first modern humans traversing unknown territory in Asia and finally crossing the sea into Australia.
Studying DNA can let you go back for hundreds and hundreds of generations, and, after many complex computer simulations, we have strong statistical evidence that makes us pretty confident that the story of the first major human dispersal is correct, said Rasmus Nielsen, who was a part of team that analyzed and confirmed the DNA sequences. Scientists now have the ability to read the chronological record of human evolution and ethnic relationships by investigating human genes.
Yet, how the Aboriginal Australians arrived on the continent despite numerous ocean barriers remains a mystery.
It was a truly amazing journey that must have demanded exceptional survival skills and bravery, said Willerslev.