The first complete sequences of the Y chromosomes of aboriginal Australian men have revealed a deep indigenous genetic history tracing all the way back to the initial settlement of the continent 50.000 years ago, according to a study published online in the journal Current Biology on February 25, 2016. The open-access article is titled “Deep Roots for Aboriginal Australian Y Chromosomes.” The study, by researchers from the Wellcome Trust Sanger Institute and collaborators at La Trobe University in Melbourne and several other Australian institutes, challenges a previous theory that suggested an influx of people from India into Australia around 4,000 to 5,000 years ago. This new DNA sequencing study focused on the Y chromosome, which is transmitted only from father to son, and found no support for such a prehistoric migration. The results instead show a long and independent genetic history in Australia. Modern humans arrived in Australia about 50,000 years ago, forming the ancestors of present-day aboriginal Australians. They were amongst the earliest settlers outside Africa. They arrived in an ancient continent made up of today's Australia, Tasmania, and New Guinea, called Sahul, probably thousands of years before modern humans arrived in Europe. 5,000 years ago, dingos, the native dogs, somehow arrived in Australia, and changes in stone tool use and language around the same time raised the question of whether there were also associated 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 5,000 ago.
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