Modern humans arrived in Australia about 50,000 years ago. They were the earliest settlers outside of Africa forming the ancestors of present-day Aboriginal Australians. Researchers have been sequencing the Y chromosome of Aboriginal volunteers to investigate their ancestry.  The results of this study refute previous studies suggesting that about 5,000 years ago there was a mixing of Aboriginal and Indian populations, and rather confirm the archaeological record.

Source: The Archaeology News Network: Genetics reveal 50,000 years of independent history of aboriginal Australian people