A young girl’s tooth found in a cave in Laos has been revealed to belong to a group of prehistoric human relatives known as the Denisovans, and this discovery is helping researchers better understand modern human evolution.
The Denisovans are relatively recently discovered human relatives, as their remains were first discovered in a Siberian cave in northern Russia in 2010. Other remains have since been discovered, including bones from as early as least 200,000 years old and a jawbone found in Tibet.
However, the discovery of the tooth, a molar, in Laos is the first time Denisovans have been found in Southeast Asia and provides a connection to modern humans living in the area today. Their findings were published Tuesday in the journal Nature Communications.
“When we found the tooth, we were surprised because we weren’t looking for Denisovans or even anticipating this type of discovery,” said Laura Shackelford, co-author and paleoanthropologist at the University of Illinois at Urbana. -Champaign, to USA TODAY via email.
The tooth was found near Tam Ngu Hao in a place known as Cobra Cave, about 150 miles north of Laos’ capital, Vientiane. It looks like a modern human tooth, the only difference being the cusp and the ridges on its surface. Found in 2018, the fossil likely ended up in the cave during a flood, as it was found among other animal fossils.
“This is the first time we’ve found something this far south, so finding the molar changes our understanding of the Denisovans’ geographic distribution,” said study co-author and professor Eske Willerslev. at the University of Copenhagen. in Denmark, said in a statement.
The humid conditions in Laos meant that the tooth’s DNA was not well preserved, but by analyzing the sediment the tooth was in, the researchers were able to estimate that the tooth was between 131,000 and 164,000 years old. Ancient proteins found in the fossil suggested it belonged to a young woman from Denisovan, between the ages of 3 and 8.
“Because the molar had not yet erupted, so not worn down, we could also assess the girl’s age with great certainty,” said Fabrice Demeter, lead author of the study and assistant professor at the University. from Copenhagen.
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Researchers believe the discovery of the Denisovan in the region adds another piece to the puzzle of human evolution. They knew that the modern natives of the Philippines, Australia, and the Oceanian region of Melanesia shared 5% of their DNA with the Denisovans, as well as other Southeast Asian populations, but the researchers didn’t know. not how it happened.
The tooth proves the species was in the area and at some point interbred with modern humans in Southeast Asia.
“The Tam Ngu Hao 2 molar provides hard evidence of what we previously knew based on this genetic data,” Shackelford said.
Denisovans are related to Neanderthals. The two species existed at the same time, but they never intermingled geographically. The Denisovans are also less well known because they were discovered so recently.
“We really have no idea what they looked like or how they might be similar or different from modern humans or Neanderthals,” Shackelford said.
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But what the tooth also shows is that the Denisovans were very adaptable to extreme weather conditions. The original location where they were found in Siberia indicates that they were able to live in the cold Arctic conditions like Neanderthals, but they could also adapt to the tropical region of South Asia. -East.
Shackleford added that they were only scratching the surface of understanding the Denisovans, but the goal is to find more fossils in hopes of getting a sense of their growth and development, and what to do with it. what they might have looked like.
“Given that there are only a handful of fossils, there is even more uncertainty,” she said.
Follow Jordan Mendoza on Twitter: @jordan_mendoza5.
