Child’s tooth could offer clues to ancient human relative

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

Researchers believe the discovery proves that Denisovans – a now-extinct branch of humanity – lived in the warm tropics of southeast Asia.

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

Scientists first discovered them while working in a Siberian cave in 2010 and finding a finger bone of a girl belonging to a previously unidentified group of humans.

Using only a finger and a wisdom tooth found in the Denisova Cave, they extracted an entire genome of the group.

Researchers then found a jawbone in 2019 on the Tibetan Plateau, proving that part of the species lived in China as well.

Aside from these rare fossils, the Denisova man left little trace before disappearing – except in the genes of human DNA today.

Through interbreeding with Homo sapiens, Denisovan remnants can be found in current populations in southeast Asia and Oceania.

Aboriginal Australians and people in Papua New Guinea have up to five per cent of the ancient species’ DNA.

Scientists concluded “these populations’ modern ancestors were ‘mixed’ with Denisovans in southeast Asia”, said Clement Zanolli, a paleoanthropologist and co-author of the study published Tuesday in Nature Communications.

But there was no “physical proof” of their presence in this part of the Asian continent, far from the freezing mountains of Siberia or Tibet, the researcher at the French National Centre for Scientific Research told AFP.

This was the case until the group of scientists began searching in the Cobra Cave in northeast Laos.

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

The tooth immediately appeared to have a “typically human” shape, explained Zanolli.

The study said, based on ancient proteins, the tooth belonged to a child, likely female, aged between 3.5 and 8.5 years old.

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