Native Australians weren't, as thought, isolated from the rest of the world for 40,000 years: they absorbed a wave of migration from India just 4,000 years ago, a genetic study shows.
Researchers at the Max Planck Institute for Evolutionary Anthropology in Germany say they've found evidence of substantial gene flow between Indian populations, as well as a common origin for Australian, New Guinean and the Philippine Mamanwa populations.
Australia holds some of the earliest archaeological evidence for the presence of modern humans outside Africa, with the earliest sites dated to at least 45,000 years ago. It's been generally believed that, following the initial dispersal of people into the joint Australia-New Guinea landmass, there was no contact between Australia and the rest of the world until the arrival of Europeans in the 18th century.
But an analysis of the genetic variation across the genome from aboriginal Australians, New Guineans, island Southeast Asians and Indians suggests that there was a substantial gene flow from India to Australia 4,230 years ago.
"Interestingly, this date also coincides with many changes in the archaeological record of Australia, which include a sudden change in plant processing and stone tool technologies, with microliths appearing for the first time, and the first appearance of the dingo in the fossil record," says researcher Irina Pugach.
"Since we detect inflow of genes from India into Australia at around the same time, it is likely that these changes were related to this migration."
The analysis also reveals a common origin for populations from Australia, New Guinea and the Mamanwa – a Negrito group from the Philippines – which now appear to have split from each other about 36,000 years ago.
"This finding supports the view that these populations represent the descendants of an early ‘southern route’ migration out of Africa, while other populations in the region arrived later by a separate dispersal," says researcher Mark Stoneking.
Interestingly, the Indian immigrants appear to have brought with them the dingo, the wild dog that roams the country. It seems that while dingo DNA appears to have originated in southeast Asia, morphologically, the dingo most closely resembles Indian dogs.