DNA analysis of a 90-year-old hair sample reveals that Aboriginal Australians left Africa much earlier than Europeans and East Asians
New research in the journal Science presents a number of firsts for Aboriginal Australians.
The first genome analysis of an Aborigine reveals that these early Australians took part in the first human migration out of Africa. They were the first to arrive in Asia some 70,000 years ago, roaming the area at least 24,000 years before the ancestors of present-day Europeans and Asians. They were also the first to live in Australia, according to DNA results of a 90-year-old hair sample of a young man that link Aborigines to the first inhabitants of this part of the world about 50,000 years ago.
This study, however, is not the first to contradict the popular theory that modern humans came from a single out-of-Africa migration wave into Europe, Asia, and Australia. But it does deal it a huge blow by confirming that Aboriginal Australians took part in the first of two rounds of human relocation.
"Aboriginal Australians descend from the first human explorers," explains lead author and University of Copenhagen professor Eske Willerslev in a news release. "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 ... traversing unknown territory in Asia and finally crossing the sea into Australia."
In the gallery below, get an up-close look at the Aboriginal Australian hair specimen behind this landmark study. Then, in the Q&A with co-author and University of California, Berkeley biologist Rasmus Nielsen that follows, learn more about the backstory of this sample, how genome-sequencing works, and the technology that led to these discoveries.
What were your team's key findings, and why are they so significant?
Anthropologists have long been interested in finding out how humans have dispersed. Most agree that modern humans evolved in Africa about 50 to 100 thousand years ago and thereafter spread to the rest of the world. But the consensus stops there.
Some anthropologists believe in the hypothesis of a so-called Southern Route or the idea that Aboriginal Australians descended from an early wave of dispersal of modern humans through Southern Asia. Most other population groups outside Africa are, according to this theory, descendants of a separate, more recent wave of dispersal. But others believe there was only one major wave. It has also been hotly debated if Aboriginals living in Australia today descend from the modern humans we know were in this area 50,000 years ago.
To resolve these debates, we sequenced the genome of an Australian Aboriginal using a 90-year-old hair sample. We analyzed the DNA computationally, and compared it to genomes of individuals from other geographic regions. We found that this individual must have descended from an early dispersal wave different from the one leading to East Asians and Europeans and that humans dispersed in two major waves of migration out of Africa. Our results also confirm that Aboriginal Australians are descendants of the first wave of migrants reaching Australia.