Australasian Science: Australia's authority on science since 1938

DNA Reveals Diversity of Ancient Australians

The ancestors of Aboriginal Australians and Papua New Guineans diverged from Eurasian populations between 51,000 and 72,000 years ago, according to a new DNA analysis of 83 Indigenous Australians. The finding supports the idea that humans spread out of Africa in a single event.

The study, published in Nature (http://tinyurl.com/h5mgzuf), is the first extensive investigation of DNA diversity in Aboriginal Australians. Prior to this study, only three Aboriginal Australians had their full DNA sequences described.

The researchers found that Aboriginal Australians and Papuans from New Guinea are closer to each other than to any other present-day worldwide populations they looked at. This is consistent with the idea that they both originated from a common ancestral population that initially colonised the single continent Sahul, which encompassed Australia, Tasmania and New Guinea.

The study found that Aboriginal Australians and Papuans diverged from Eurasians ~58,000 years ago following a single out-of-Africa dispersal. Aboriginal Australians and Papuans later diverged ~37,000 years ago, long before the physical separation of Australia and New Guinea. These people, coming from mainland Asia and travelling into Australia, were the ancestral population to most, if not all, modern Australians.

Subsequently, the ancestral Australian population differentiated ~31,000 years ago into subgroups. The formation of the central desert was a likely barrier to migrations.

The study also reported that Aboriginal Australians living in desert conditions may have developed specific biological means of coping with those highly challenging environments. “Unique morphological and physiological adaptations have been identified in Aboriginal Australians living in the desert areas today,” says communicating author, Prof David Lambert of Griffith University. “In particular, the evidence suggests that desert groups are able to withstand sub-zero night temperatures without showing the increase in metabolic rates observed in Europeans under the same conditions.”