Baby teeth, 130,000 years old, give clues to ancient human relatives

Baby teeth, 130,000 years old, give clues to ancient human relatives

Little is known about the Neanderthals’ cousin Denisovan.

Paris:

At least 130,000-year-old baby dentists found in caves in Laos could help scientists unravel more information about early human cousins, a study said on Tuesday.

Researchers believe the discovery proves that Denisovan – a now-extinct branch of humanity – lived in the tropics of Southeast Asia.

Little is known about the Neanderthals’ cousin Denisovan.

Scientists first discovered them in 2010 while working in a cave in Siberia and finding the finger bones of a girl from a previously unknown human group.

Using only a finger and a wisdom tooth found in the Denisova cave, they pulled out a complete genome of the group.

Researchers then found a jaw bone in the Tibetan plateau in 2019, proving that part of the species also lives in China.

In addition to these rare fossils, Denisova left little traces of man before he disappeared – without the genes in today’s human DNA.

By interbreeding with Homo sapiens, Denisovan remains can be found in the current populations of Southeast Asia and Oceania.

Indigenous Australians and the people of Papua New Guinea have up to five percent of the DNA of the ancient species.

Cobra Cave Discovery

Scientists have concluded that the modern ancestors of this population were “mixed” with the Denisovans of Southeast Asia, said Clement Janoli, a paleontologist and co-author of the study published Tuesday in Nature Communications.

Researchers at the French National Center for Scientific Research told AFP there was no “physical evidence” of their presence in this part of Asia, far from the frozen mountains of Siberia or Tibet.

This was before a team of scientists began exploring the Cobra Cave in northeastern Laos.

Cave experts discovered the area in 2018 on a hill next to the Tam Pa Ling Cave, where the remains of ancient humans have already been found.

The tooth immediately appeared to have a “normal human” shape, Janoli explained.

According to the study, based on ancient proteins, the tooth is a baby, probably female, between the ages of 3.5 and 8.5 years.

The tooth is too old for carbon-dating, and the DNA is poorly preserved due to heat and moisture, says Fabrice Demeter, a paleontherapist and co-author of the study.

After analyzing the shape of the teeth, scientists believe it was probably Denisovan who lived 164,000 to 131,000 years ago.

Neanderthal cousin

They then studied the interior of the teeth through a variety of methods, including protein analysis and a 3D X-ray reconstruction.

The internal structure of the tooth was similar to that of the molar found in the Tibetan Denisova specimen. It was clearly different from modern humans and other ancient species living in Indonesia and the Philippines.

Dmitar, a researcher at the University of Copenhagen in Denmark, said: “Proteins allow us to identify the sexes – females – and confirm their relationship to the Homo species, where the tooth is temporarily based.

The tooth structure had common features with Neanderthals, who were genetically close to Denisovan. The two species are thought to have separated about 350,000 years ago.

Xanoli explained that the researchers concluded that it was a Denisova specimen because no Neanderthal mark had been found before.

For Dimitar, 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, where their Neanderthal cousins ​​seemed more “special” in the cold west.

The last Denisovans could therefore mingle and interbreed with modern humans, who passed on their genetic heritage to the modern population of Southeast Asia during the Pleistocene.

(Except for the title, this story was not edited by NDTV staff and was published from a syndicated feed.)

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