A baby tooth could give a key to an ancient human relative

A tooth of a child at least 130,000 years old, found in a cave in Laos, could help scientists uncover more information about the man’s early cousin, the study said on Tuesday.

Researchers believe that the discovery proves that Denisov – now an extinct branch of humanity – lived in the warm tropics of Southeast Asia.

Very little is known about Denisov, a cousin of the Neanderthals.

Scientists first discovered them while working in Siberia cave in 2010 and the discovery of the finger bone of a girl belonging to a previously unidentified group of people.

Using only finger and wisdom tooth found in Denis Cave, they found the whole genome of the group.

Researchers then found the jaw in 2019 in the Tibetan Plateau, proving that part of the species also lived in China.

Apart from these rare fossils, Denisov left no traces before disappearing – except in the genes of modern human DNA.

Through a cross with Homo sapiens the remains of Denisova can be found in the current populations of Southeast Asia and Oceania.

The aborigines of Australia and the people of Papua New Guinea have up to five percent of the DNA of the ancient species.

Opening of the Cobra Cave

Scientists have concluded that “modern ancestors of these populations” mixed “with Denisovans in Southeast Asia,” said Clement Zanoli, a paleoanthropologist and co-author of a study published Tuesday in The nature of communication.

But there was no “physical evidence” of their presence in this part of the Asian continent, far from the frosty mountains of Siberia or Tibet, a researcher from France’s National Research Center told AFP.

This was until a group of scientists began searching the Cobra Cave in northeastern Laos.

Cave experts discovered a site in the mountain in 2018 near the cave Tam Pa Ling, where the remains of ancient people have already been found.

The tooth immediately took on a “typical human” shape, Zanoli explained.

The study says that on the basis of ancient proteins the tooth belonged to a child, probably a woman, aged 3.5 to 8.5 years.

But the tooth is too old for carbon dating, and the DNA is poorly preserved because of the heat and humidity, said paleoanthropologist and study co-author Fabrice Demeter.

After analyzing the shape of the tooth, scientists believe that most likely it was Denis, who lived from 164,000 to 131,000 years ago.

Neanderthal cousin

They then examined the inside of the tooth using a variety of techniques, including protein analysis and 3D X-ray reconstruction.

The internal structure of the tooth was similar to the molars found in a Tibetan denim specimen. It was clearly different from modern people and others ancient species who lived in Indonesia and the Philippines.

“Proteins have allowed us to identify gender – female – and confirm its association with the Homo species,” said Demeter, a researcher at the University of Copenhagen in Denmark, where the tooth is temporarily located.

The structure of the tooth had common features with the Neanderthals, who were genetically close to the Denisovans. It is estimated that the two species diverged about 350,000 years ago.

But Zanoli explained that the researchers concluded that it was a copy of Denisov, because traces of Neanderthals so far east were not found.

For Demeter, the discovery shows that the Denisovans occupied this part of Asia and adapted to a wide range of environments, from cold altitudes to tropical climates, while their Neanderthal relatives seemed more “specialized” in the cold western regions.

Thus, the last Denisovites could meet and interbreed modern peoplewho passed on their genetic heritage to the modern population of Southeast Asia in the Pleistocene.

© 2022 AFP