- A tooth found in a cave in Laos was found to belong to an ancient human species called Denisovans.
- The tooth, most likely from a girl, places extinct humans in Southeast Asia for the first time.
- This solves the mystery of how Denisovan genes are found in humans in Southeast Asia today.
The remains of a now-extinct ancient human species called Denisovans were found in Southeast Asia for the first time.
Scientists were looking for Denisovan remains in the area because they knew that some of their genes have been passed on to modern human populations in Southeast Asia today.
But until now, scientists had been unable to formally place them there.
A single tooth over 130,000 years old that belonged to a young Denisovan was found in a cave in Laos.
“That was the big mystery: why is Denisovan DNA found in these Southeast Asian populations, but not found in Eurasia or anywhere else,” said Mike Morley, an associate professor at Flinders University’s Microarchaeology Laboratory and study author. he said in a press release.
“This is the ‘smoking gun’ type, this tooth,” he said.
The tooth was found in a cave called Tam Ngu Hao 2 in Laos in 2018. The findings were published Tuesday in the peer-reviewed journal Nature Communications.
Denisovan remains have only been found in two other locations.
The Denisovans are a species of ancient humans. Like the Neanderthals, Homo naledi or Homo bodoensis, they died out while modern humans survived.
This subgroup of ancient humans has been particularly elusive because so few remains have been discovered to date.
Most of the remains have been found in Denisova Cave in Siberia, thousands of miles north of Laos.
But scientists knew that these ancient humans must have descended to Southeast Asia, where they would have interbred with modern humans. A 2020 study found that a small number of Denisovan genes can be found in some populations in Southeast Asia.
The Laos discovery is only the second to place Denisovan outside of Siberia.
This cave, where the first Denisovan remains were found in 2008, was probably inhabited by Denisovans from about 300,000 years ago to about 50,000 years ago. It has taught us that these humans probably used stone tools and that they probably interbred with humans and Neanderthals.
A 2020 study revealed that a jaw found in Baishiya Karst Cave in Tibet, Xiahe County, Gansu, China was from a Denisovan who lived about 160,000 years old.
The clues reveal the origin of the tooth
The conditions in the cave mean that the tooth’s DNA has been too poorly preserved to read. But scientists found other clues about its origins.
An analysis of the proteins in the tooth revealed that it probably belonged to a girl, between 3.5 and 8.5 years old.
The internal structure of the tooth also resembles the shape of those found in the Tibetan specimen of Denisovans, indicating that the child was Denisovan.
The rock around the tooth could also be dated, indicating that the boy lived between 164,000 and 131,000 years ago.
Local children saw the tooth for the first time.
Scientists were first told about the fossil-rich cave by local children in 2018, Laura Shackelford, a paleoanthropologist at the University of Illinois and a co-author of the study, told The New York Times.
When they got to the closet-sized cavity where the children said they found the bones, “all you could see were bones and teeth, embedded in the walls and ceiling of this cave,” Shakelford said.
“They were everywhere,” he said, according to the Times.
Most of these were bones from pigs, deer and pygmy elephants, which had teeth marks that suggested they were part of a meal, the Times reported. But among the fossils, scientists found a single tooth belonging to the ancient human.