The ground-breaking study used a single lock of hair from the Duckworth Collection at the University of Cambridge. It shows that the direct ancestors of modern Aboriginal Australians began a journey of colonisation and adaptation some 70,000 years ago, more than 20,000 years before the ancestors of Europeans and Asians dispersed throughout Eurasia, demonstrating that the continent was colonised by more than one wave of people originally from Africa.
The international team working on the project was led by the University of Copenhagen, and included a UK collaboration involving researchers from Cambridge, Imperial College London and University College London. Their findings are published today in the journal, Science.
Although there is good archaeological evidence that shows humans arrived in Australia as early as 50,000 years ago, this genome study re-writes the story of their journey. It provides good evidence that Aboriginal Australians are descendants of the earliest modern explorers. This is contrary to the previous and most widely accepted theory that all modern people in Europe and Asia derive from a single, out-of-Africa migration wave into Europe, Asia and Australia.
The study derived from a lock of hair donated to the British anthropologist A.C. Haddon by an Aboriginal man from the Goldfields region of Western Australia in the early 20th century and kept by the Duckworth Laboratory at Cambridge. One hundred years later, researchers have isolated DNA from this same hair, using it to explore the genetics of the first Australians and to provide insights into how humans first dispersed across the globe.
By sequencing the genome, which was shown to have no genetic input from modern European Australians, the researchers were able to establish 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 an early human expansion some time during this period, while the ancestors of Europeans and Asians were still somewhere in Africa or the Middle East.
As a result, the study establishes Aboriginal Australians as the population outside Africa with the longest association with the land on which they live today. It has been carried out with the full endorsement of the Goldfields Land and Sea Council, the organisation that represents the Aboriginal traditional owners for the region.
Dr. Marta Mirazon Lahr, from the Leverhulme Centre for Human Evolutionary Studies, where the Duckworth Collection is based, said: "This study is a wonderful example of how new techniques can bring alive old collections, and enhance their importance. We are delighted that the likely descendants of the Australian man – today members of the Goldfields Land and Sea Council, have been such a positive part of this research."
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. Through analysis of museum collections, and in collaboration with descendant groups, researchers can now study the genetic history of many indigenous populations worldwide, even where groups have recently moved about or intermingled.