Previously archaeologists have argued that the change in skeletal features seen in Aborigine fossils—from slender about 40,000 years ago to stocky about 13,000 years ago—signals a mixing between modern humans and more ancient populations such as the Neandertals (often spelled "Neanderthals").
But the new DNA results suggest no such intermingling occurred.
"This result provides strong evidence for the 'Out of Africa' hypothesis and gives the multiregionalists much less room to move," said Richard Gillespie, visiting fellow in the Division of Archaeology and Natural History at the Australian National University in Canberra. Gillespie was not involved in the study.
The research will be published in tomorrow's edition of the journal Proceedings of the National Academy of Sciences.
No Outside Influence
The findings may also influence the debate over whether Asian groups migrated to Australia more recently.
Over the last 10,000 years the archaeological record in Australia has changed significantly, including the first appearance of the dingo—a type of dog—and new stone tool industries, "which (may) represent the intrusion of new human migrations into the continent," study co-author Endicott said.
However, the distinctiveness of the Aborigine DNA means the population has remained relatively isolated, ruling out the possibility of later influxes into Australia from Asia.
"If there had been Asian migrations, we would have expected to see regional specific subgroups in the Aboriginal DNA," Kivisild, of Cambridge, said. "But they were completely absent."
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