The researchers completely sequenced the volunteers' Y-chromosomes - the sex chromosomes that are only passed on from father to son. The results, they say, refute a previous Y-chromosome study, which suggested an influx of people from India into Australia 4-5 thousand years ago. Instead, the sequences obtained from 13 Aboriginal volunteers were very distinct from those of Indian males, suggesting a long and independent genetic history in Australia.
This is in agreement with the archaeological record, according to which modern humans arrived in Australia about 50 thousand years ago, amongst the earliest settlers outside Africa.
Lesley Williams, who was responsible for the liaison with the Aboriginal community, said: “As an Aboriginal Elder and cultural consultant for this project I am delighted, although not surprised, that science has confirmed what our ancestors have taught us over many generations, that we have lived here since the Dreaming.”
However, the puzzle of Australia's history still requires further research. For example, Australia's native dogs, the dingos, somehow arrived five thousand years ago. How they got to Australia remains unclear. And as there were also changes in stone tool use and language around that time, the question was raised whether this was associated with genetic changes in the Australian Aboriginal population.
At least two previous genetic studies, one of which was based on the Y chromosome, had proposed that these changes could have coincided with mixing of Aboriginal and Indian populations about 5 thousand years ago.
And while the present study stongly supports the view of an uninterrupted history of Aboriginal people over the past 50,000, the researchers acknowledge that to completely rule out external genetic influences the genetic analysis will need to be expanded beyond the Y chromosome.