Neanderthal DNA may refute 65,000-year-old date for human occupation in Australia, but not all experts are convinced
Humans did not arrive in Australia 65,000 years ago and have probably reached land that the land is approximately 50,000 years ago, reports a controversial new paper.
The reasoning behind the observation is that modern humans did not cut Neanderthal About 50,000 years ago, but Aboriginal Australians have a small percentage of Neanderthal DNA. Thus, the first Australians could only have arrived after humans coupled with the Neanderthals.
But we cannot yet exclude archaeological evidence that places humans on the continent much earlier than genetic models, according to other experts.
In a research report published Sunday (June 29) in the review Archeology in Oceaniaarchaeologists Jim Allen of the University of Trobe in Australia and James O’Connell From the University of Utah recently used Neanderthal DNA evidence, suggesting that Australia was not occupied by humans 50,000 years ago.
The new theory of Allen and O’Connell is based on Two recent DNA studies This revealed that Neanderthals and humans probably got on in Europe during a long “pulse” between 50,500 and 43,500 years. Since all living humans outside Africa At least 2% Neanderthal DNAincluding Aboriginal Australians, this means the first Homo sapiens In Australia, Neanderthal roots – and these roots cannot come back much earlier than 50,000 years ago.
Researchers interested in the first humans in Australia focused mainly on archaeological sites in Southeast Asia and Oceania, through the modern borders of Indonesia, Australia and various islands, also known as Paleocontinent Sahul.
“The initial colonization of Sahul is important because it occurs late Pleistocene [129,000 to 11,700 years ago]Who coincides with a major expansion in the distribution of anatomically modern human populations outside Africa, “O’Connell told Live Science.
The archaeological evidence of human occupation in Sahoul are largely aligned with genetic evidence, wrote Allen and O’Connell in their study. All the archaeological sites, except one, are dated between 43,000 and 54,000 years, which means that humans could have mingled with the Neanderthals in Eurasia, then head east.
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Archeology against genetics
But archaeological evidence on a site called Madjedbebe in the far north of the northern territory of Australia suggest that the region may have been occupied much earlier – at least 65,000 years ago.
Archaeologists have recovered human artefacts, including stone tools and ocher “Pencils”, from Madjedbebe Rock Shelter and published their conclusions in a 2017 study. However, a difficulty getting out with the artifacts was the abundant amount of sand on the ground of the rock shelter, which can move easily and drop the artifacts further, which makes them older than they are.
Although the research team took action To counter this problem and land on a date of 65,000 years, the timing of the occupation of Madjedbebe is still uncertain because it is by far the oldest archaeological site in Australia, which makes it an aberrant value.
“This does not necessarily mean that the data is wrong,” said O’Connell, “but it means that if the data is good, the people responsible for Madjedbebe are not ancestral to a certain significant measure for modern Sahul populations.”
But the new theory of Allen and O’Connell is strongly based on hypotheses in the DNA model and in the first human behaviors, several researchers suggested in a comment, also published Sunday in Archeology in Oceania.
“The archaeological and molecular dates of Sahul are still at an early stage of development,” wrote Peter VethArchaeologist at the University of Australia-Western, “can we rely on current hypotheses underlying these molecular clocks to test Australian archaeological evidence?”
Adam BrummArchaeologist at Griffith University in Australia, wrote that the archaeological sites of Southeast Asia, as on Sulawesi in Indonesia, have in fact convincing proof of precocious rocky art that goes up at least 51,200 years ago.
“Recalling that we only have minimum The ages for rock art, I think that there is a very real possibility that the people who created the first works of art in Sulawesi were part of the same wider cultural group which continued to colonize Sahul about 65,000 years ago, “wrote Brumm.
O’Connell and Allen, however, think that this type of works of art, intensive maritime navigation and the creation of complex artefacts are all linked to a change in human behavior which started around 50,000 years ago, sometimes called the Paleolithic Revolution. In a narrow time window, they wrote, these first humans “began the process of moving archaic homes and various environments in Europe and Asia”.
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But in their commentary, archaeological scientists Huw Groucut And Eleanor Scerri questioned this idea of a “revolution” in a behavior that occurred when humans met the Neanderthals.
“In Africa, decades of research now clearly show the presence of complex behaviors, tens of thousands of years earlier than the supposed revolution, and undoubtedly occurring in a gradual and fragmentary way,” wrote Groucutt and Scerri.
Although genetic and archaeological evidence is currently in disagreement, it is important to remember that there are major shortcomings in the two data sets, which means that there is no solid evidence in favor of the date of pre- or after 50,000 years for the first occupation of Sahul, Groucutt and Scerri.
But even if the archaeological evidence does not currently refute the theory of Allen and O’Connell, Brumm wrote: “I think that this evidence arrives, however, and it will have great implications for our understanding of the old Sahul.”
