Out of Africa x2: Rewriting Human Origins

Big news today for those interested in our human origins, or in Australia, or anything that lies between the two: a new study published in Science indicates that Australian aboriginals migrated out of Africa at least 24,000 years before the groups that would become modern Europeans and Asians. This challenges the established theory that there was only one big migration out of Africa, and establishes Aboriginal Australians as the group with the longest claim to their land in the world. 

And fun fact: this phenomenal discovery came from a lock of hair donated to an anthropologist 100 years ago. Oh science.

There are currently ~125 news stories about this via Google; here’s the word from Science Daily:

In an exciting development, an international team of researchers has, for the first time, pieced together the human genome from an Aboriginal Australian…

The genome, shown to have no genetic input from modern European Australians, reveals that the ancestors of the Aboriginal man separated from the ancestors of other human populations some 64-75,000 years ago. Aboriginal Australians therefore descend directly from the earliest modern explorers, people who migrated into Asia before finally reaching Australia about 50,000 years ago. In showing this, the study establishes Aboriginal Australians as the population with the longest association with the land on which they live today…

Previously, the most widely accepted theory was that all modern humans derive from a single out-of-Africa migration wave into Europe, Asia, and Australia. In that model, the first Australians would have branched off from an Asian population, already separated from the ancestors of Europeans. However, this study shows that when ancestral Aboriginal Australians began their private journey, the ancestors of Asians and Europeans had not yet differentiated from each other…

Professor Eske Willerslev from the University of Copenhagen, who headed the study, explains: “Aboriginal Australians descend from the first human explorers. 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. It was a truly amazing journey that must have demanded exceptional survival skills and bravery.”

The study has wide implications for understanding of how our human ancestors moved across the globe. So far the only ancient human genomes have been obtained from hair preserved under frozen conditions. The researchers have now shown that hair preserved in much less ideal conditions can be used for genome sequencing without risk of modern human contamination that is typical in ancient bones and teeth.

What could it have been like, crossing through Asia and crossing the sea to Australia tens of thousands of years ago, in wilderness completely untouched by humans? Crazy scary, I bet.

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