Aboriginal Australian men were in isolation for 50,000 years since their initial settlement, a new DNA sequencing study found. The findings challenged the previous hypothesis suggesting the arrival of early inhabitants from India about four to five thousand years ago.
The Y chromosome is handed down from father to son. The first complete Y chromosome sequencing study found no evidence of ancient migration. Instead, it revealed a nearly 50,000-year isolation.
The modern humans who arrived in Australia almost 50,000 years ago were one of the earliest groups who settled outside of Africa. They founded the ancestry of today's Aboriginal Australians.
When the dingos (native dogs) arrived in Australia 5,000 years ago, there were also documented changes in language and stone tool usage. Experts began to question if these are linked to genetic changes with the population. Previous studies suggested that the changes could be associated with the arrival of Indian populations around the same time.
The research team included scientists from the Wellcome Trust Sanger Institute (UK), La Trobe University (Australia) and other Australian institutes. Working closely with Aboriginal Australian communities, they sequenced the Y chromosome DNA of 13 male participants.
"The data show that Aboriginal Australian Y chromosomes are very distinct from Indian ones," said study's first author Anders Bergstrom, stressing that the new study disproved the previous Y chromosome research. "Instead, the results are in agreement with the archaeological record about when people arrived in this part of the world."
Dr. John Mitchell from Melbourne's La Trobe University shared the team returned the results to the participants prior to the scientific paper's publication. Mitchell stressed the importance of years of engagement and collaboration with the Aboriginal communities.
"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," said Lesley Williams, who liaised the research team with the Aboriginal community.
To entirely rule out other genetic influences, researchers must go beyond the Y chromosome and conduct a complete DNA sequencing study. More study is required to answer the open questions about the dingo's arrival in Australia or why other early settlers such as the Polynesians didn't settle on the same continent.
The new study was published in the Current Biology journal on Feb. 25.
Photo: Corey Leopold | Flickr