澳大利亚人与印度人有相似基因
Australia experienced a wave of migration from India about 4,000 years ago, a genetic study suggests.
一项遗传学研究显示，大约4000年前印度人经历了一波迁徙到达澳大利亚。
It was thought the continent had been largely isolated after the first humans arrived about 40,000 years ago until the Europeans moved in in the 1800s.
But DNA from Aboriginal Australians revealed there had been some movement from India during this period.
The researchers believe the Indian migrants may have introduced the dingo（澳洲野狗） to Australia.
In the Proceedings of the National Academy of Sciences, they say that the fossil record suggests the wild dogs arrived in Australia at around the same time.
They also suggest that Indians may have brought stone tools called microliths（细石器） to their new home.
Ancient origins
"For a long time, it has been commonly assumed that following the initial colonization, Australia was largely isolated as there wasn't much evidence of further contact with the outside world," explained Prof Mark Stoneking, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
"It is one of the first dispersals of modern humans - and it did seem a bit of a conundrum（难题，谜语） that people who got there this early would have been so isolated."
To study the early origins of Australia's population, the team compared genetic material from Aboriginal Australians with DNA from people in New Guinea, South East Asia and India.
By looking at specific locations, called genetic markers, within the DNA sequences, the researchers were able to track the genes to see who was most closely related to whom.
They found an ancient genetic association between New Guineans and Australians, which dates to about 35,000 to 45,000 years ago. At that time, Australia and New Guinea were a single land mass, called Sahul, and this tallies with the period when the first humans arrived.