The bones of a teenage hunter-gatherer, who died more than 7,000 years ago on the Indonesian island of Sulawesi (Celebes), tell the story of a previously unknown group of humans.
This human lineage has never been found anywhere else in the world, according to new research published Wednesday in the journal Nature.
‘We have discovered the first ancient human DNA in the region of the island between Asia and Australia, known as’ Wallacea’, which provides a new perspective on the genetic diversity and population history of early modern humans in this part of the world little understood, ”says study co-author Adam Brumm, a professor of archeology at Griffith University’s Australian Research Center for Human Evolution.
Early modern humans used the Wallacea Islands – primarily Indonesian islands that include Sulawesi, Lombok, and Flores – when they crossed from Eurasia to the Australian mainland more than 50,000 years ago, the researchers believe. However, the exact route or how they navigated this junction is unknown.
‘They must have done it using relatively sophisticated boats of some kind, as there were no land bridges between the islands, even during the glacial peaks of the last ice age, when global sea levels were up to 140 meters (459 feet) lower. that they are today, ”Brumm explained.
Rock paintings and tools have suggested that humans lived on these islands 47,000 years ago, but the fossil record is scarce and ancient DNA degrades more rapidly in tropical climates.
The Toalean Culture
However, researchers discovered the skeleton of a 17-18-year-old woman in Sulawesi in 2015, whom they nicknamed Bessé. Her remains were buried in the cave – part of an archaeological site called Leang Panninge – 7,200 years ago. She was part of the Toalean culture.
“Toaleans is the name archaeologists have given to a somewhat enigmatic culture of prehistoric hunter-gatherers, who lived in the forested plains and mountains of southern Sulawesi from about 8,000 years ago to about the 5th century AD,” Brumm noted. . “They made very distinctive stone tools (including well-crafted, tiny arrowheads known as Maro’s points ) found nowhere else on the island or in Indonesia.”
The young hunter-gatherer is the first largely complete and well-preserved skeleton associated with this culture.
The study’s lead author, Selina Carlhoff, was able to recover DNA from the wedge-shaped petrous bone at the base of the skull.
“It was a great challenge, as the remains had been heavily degraded by the tropical climate,” Carlhoff, a doctoral student at the Max Planck Institute for the Science of Human History in Jena, Germany, said in a statement.
The Knowledge Hidden In The DNA
The work to recover the genetic information was difficult but it was worth it.
The young woman’s DNA showed that she was descended from the first wave of modern humans that entered Wallacea 50,000 years ago. This was part of the initial colonization of ‘Greater Australia’, or the combined ice age landmass of Australia and New Guinea. These are the ancestors of today’s indigenous Australians and Papuans.
And it turns out that the oldest genome traced to the Wallacea Islands revealed something else: previously unknown ancient humans.
“They also share ancestry with a separate and distinct group from Asia that probably arrived after the colonization of Greater Australia, because modern indigenous Australians and Papuans do not share ancestry with this group,” Brumm said.
“Previously, it was thought that the first time that people with Asian genes entered Wallacea was around 3,500 years ago, when Austronesian-speaking farmers from Neolithic Taiwan crossed the Philippines and arrived in Indonesia,” he added.
“This suggests that there might have been a different group of modern humans in this region that we really had no idea about until now, as archaeological sites are very rare in Wallacea and ancient skeletal remains are rare.”
The analyzed genome included another trace of an enigmatic and extinct group of humans: the Denisovans. The handful of fossils that indicate these first humans existed are largely from Siberia and Tibet.
“The fact that their genes are found in the Leang Panninge hunter-gatherers supports our earlier hypothesis that Denisovans occupied a much larger geographic area than previously understood,” said study co-author Johannes Krause, professor of archaeogenetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
But when this DNA was compared to that of other hunter-gatherers living west of Wallacea at the same time, this DNA did not contain any trace of Denisovan DNA.
‘The geographic distribution of Denisovans and modern humans may have overlapped in the Wallacea region. It may well be the key place where the Denisova people and indigenous Australian and Papuan ancestors intersected, ”speculated study co-author Cosimo Posth, a professor at the University of Tübingen’s Senckenberg Center for Human Evolution and Paleoenvironment in Frankfurt.
Researchers don’t know what happened to Toalean culture, and this latest discovery is one piece of the puzzle as they try to understand the ancient genetic history of humans in Southeast Asia. Brumm hopes that older DNA from the Toalean people can be recovered to “reveal their diversity and broader ancestral history.”