After analyzing the DNA of 800 people from more than 270 populations, including a large number of aboriginal people in Australia and Papua New Guinea, the researchers found genetic evidence for a migration of humans out of Africa about 100,000 years ago – long before the migration that most modern Europeans, Asians, and Australians are descended from, which came about 60,000 years ago.
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But in natives from Papua New Guinea, the researchers found that 2.0 percent of their genomes show DNA evidence of an earlier migration of home sapiens out of Africa.
The analysis suggests Indigenous Australians and Papuans arrived in their present homelands some 50,000 years ago and were likely the first humans to cross an ocean, as well as perhaps the oldest living civilazation.
What we did find was unique genetic variations specific to Aboriginal Australians that might have given them an improved ability to withstand cold and dehydration – potential adaptations to life in the desert. This also confirms that the Indigenous Australian population is descended from the first people to inhabit Australia.
Genetic differences between Aboriginal populations were also exacerbated by the last ice age, which occurred about 20,000 to 30,000 years ago.
The studies all agree that even though a massive expansion from Africa happened, groups and civilizations were divided into substructures that found one another along the way before establishing in a continent.
Genome sequencing of Papuan and Australian aboriginal people supported the theory that humans emigrated from Africa in multiple waves, rather than a single wave, and possibly earlier than previously believed, they said.
“The genetic diversity among Indigenous Australians is incredible”, said study first author Dr. Anna-Sapfo Malaspinas, from the SIB Swiss Institute of Bioinformatics, the Centre for GeoGenetics of Copenhagen and the University of Bern.
Previous research unearthed bones from a mysterious extinct branch of the human family tree from Denisova cave in Siberia’s Altai Mountains.
Modern humans originated about 150,000 to 200,000 years ago in Africa.
They identified waves of migration across the Arabian Peninsula and Levant region during four periods: between 106,000 and 94,000 years ago; 89,000 to 73,000 years ago; 59,000 to 47,000 years ago; and 45,000 to 29,000 years ago.
Aboriginal Australians and Papuans then diversified between 25,000 and 40,000 years ago, long before Australia and New Guinea separated in the early Holocene (about 11,500 years ago). The reasons for the massive migration, although it remains as an on-going debate, could be due to environmental circumstances but what scientists do know is that this was the moment when humans started creating societies around the world.
The new study on the DNA of modern indigenous Australian populations was published in the journal Nature.
A similar conclusion is made by Eske Willerslev, a researcher from the University of Copenhagen, Danemark and his colleagues. Though simplified (The Australopithecus genus and other pre-Homo groups are lumped into one bubble of hominins), the model shows how some groups interbred while others were isolated. This implies that the group of people who ended up in the Sahul split away from others nearly as soon as the initial group left Africa.
“[And] that great genetic diversity in Aboriginal populations reflects the huge amount of time they have occupied the continent”.
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The new work takes advantage of the fact that human DNA accumulates tiny changes over time. Other assertions which appeared then were arguing that what we know as modern day population came from Africa through many migration processes. But actually, the first two papers don’t completely rule out earlier waves of migration (most of which undoubtedly did not go well, resulting in a localized extinction of that particular group of rovers).
