– The early peopling of Australia and the continent’s subsequent population history has been a matter of scientific debate for decades.
Who were the first Australians and where did they come from? So far, it has not been easy to answer this question and yet it is well-known that Australia has one of the longest histories of continuous human occupation outside Africa.
The ocean crossing from Asia to Australia is one of humanity’s great early achievements, but it’s one that is shrouded in mystery.
Why modern humans made the journey, and when, are still open questions that scientists are keen to answer because they could hold the key to understanding when our ancestors first left Africa and whether they did so in one wave or in a staggered exodus spread out over millennia.
The earliest known evidence of human occupation in Australia is a rock shelter in the Northern Territory that is about 55,000 years old, while the oldest human fossils ever discovered in Australia are about 10,000 years younger.A new DNA study can cast more light on the ancient Australian mystery. The first ever comprehensive genomic study of Aboriginal Australians reveals three important key in ancient Australian history.
A close collaboration between international research teams and representatives of Aboriginal Australian communities have resulted in a study that has uncovered several major findings on early human populations
To start with, the genomic study of Aboriginal Australians reveals that they are indeed the direct descendants of Australia’s earliest settlers and diverged from their Papuan neighbors about 37,000 years ago.
Previous DNA studies were based on only three Aboriginal Australian genomes. One was derived from a tuft of hair (taken from a deceased individual), and the other two from cell lines whose provenance is somewhat hazy.
This time scientists were able to sequence 83 modern Aboriginal Australian and 25 modern Papuan genomes. The research teams, which include six researchers from the SIB Swiss Institute of Bioinformatics and two scientists from the University of Bern used this genomic data and combined it with linguistic data to characterize the peopling of Australia. The results of the analysis highlights three important key dates in ancient Australian history.
It has often been hypothesized that the ancestors of modern Papuans and Australians must have left Africa far earlier than any other population if they were to reach New Guinea and Australia about 47,000 years ago, as suggested by the fossil record.
The researchers discovered, however, that this is most probably not the case; they estimate that around 72,000 years ago, an ancestral population common to Aboriginal Australians, Europeans and East Asians left the African continent.
Professor Laurent Excoffier of the SIB Swiss Institute of Bioinformatics and the University of Bern explains: “Discussions have been intense as to what extent Aboriginal Australians represent a separate Out-of-Africa exit to those of Asians and Europeans. We find that, once we take into account admixture with archaic humans, the vast majority of the Aboriginal Australian genetic makeup comes from the same African exit as other non-Africans.”
The Aboriginal Australians would have diverged from the Papuans 37,000 years ago, long before New Guinea and Australia became geographically separated.
Aboriginal Australians have been the subject of scientific mystery,” notes senior author Professor Eske Willerslev, from the Copenhagen-based Centre for GeoGenetics, Cambridge University and the Sanger Institute.
“How did they get there? What was their relationship to other groups? And how does their arrival change our understanding of how populations spread? Technologically and politically, it has not really been possible to answer these questions until now.”
While the authors found evidence for gene flow between sampled groups, the ancestral population of Aboriginal Australians started to become structured around 31,000 years ago thus creating the genetic diversity observed today.So maybe we have know come a step closer and can finally piece together all the missing pieces and learn the true history f ancient Australia.