Cave discovery in Laos could unlock more about human evolution's biggest mystery

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(CNN)A bony unearthed from a distant cave successful Laos is helping to sketch an chartless section successful the quality story.

Researchers judge the bony belonged to a young pistillate who lived astatine slightest 130,000 years agone and was apt a Denisovan -- an enigmatic radical of aboriginal humans archetypal identified successful 2010.

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The little molar is the archetypal fossil grounds placing Denisovans successful Southeast Asia and whitethorn assistance untangle a puzzle that had agelong vexed experts successful quality evolution.

The lone definitive Denisovan fossils person been recovered successful North Asia -- successful the eponymous Denisova cave successful Siberia's Altai Mountains successful Russia. Genetic evidence, however, has tied the archaic humans astir intimately to places overmuch further southbound -- in what's present the Philippines, Papua New Guinea and Australia.

"This demonstrates that the Denisovans were apt contiguous besides successful confederate Asia. And it supports the results of geneticists who accidental that modern humans and the Denisovans mightiness person met successful Southeast Asia," said survey writer Clément Zanolli, a researcher successful paleoanthropology astatine CNRS, the French National Center for Scientific Research and the University of Bordeaux.

Archaeologists uncovered the bony successful a spot known arsenic Cobra Cave, 160 miles (260 kilometers) northbound of Laos' capital, Vientiane, wherever excavations began successful 2018. The study, which published successful the diary Nature Communications on Tuesday, estimated the molar was betwixt 131,000 and 164,000 years old, based connected investigation of cave sediment, the dating of 3 carnal bones recovered successful the aforesaid layer, and the property of stone overlying the fossil.

The bony   was unearthered from a cave successful  Laos and belonged to a pistillate   who lived astatine  slightest  131,000 twelvemonth  ago.

"Teeth are similar the achromatic container of an individual. They sphere a batch of accusation connected their beingness and biology. They person been ever utilized by paleoanthropologists, you know, to picture taxon oregon to separate betwixt species. So for america paleoanthropologists (teeth) are precise utile fossils," Zanolli said.

Comparison with archaic quality teeth

The researchers compared the ridges and dips connected the bony with different fossilized teeth belonging to archaic humans and recovered it didn't lucifer teeth belonging to Homo sapiens oregon Homo erectus -- an archaic quality that was the archetypal to locomotion with an upright gait whose remains person been recovered crossed Asia. The cave find astir intimately resembled a bony recovered successful a Denisovan jawbone recovered connected the Tibetan plateau in Xiahe county, successful Gansu province, China. The authors said it was possible, though little likely, it could beryllium to a Neanderthal.

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"Think astir about it (the tooth) arsenic if you are traveling into (a) valley betwixt mountains. And the enactment of these mountains and valleys is precise emblematic of a species," Zanolli explained.

Analysis of some macromolecule successful enamel from the bony suggested that it belonged to a female.

Denisovan DNA lives connected successful immoderate humans contiguous because, erstwhile our Homo sapiens ancestors encountered the Denisovans, they had enactment with them and gave commencement to babies -- thing geneticists telephone admixture. This means we tin look backmost into quality past by analyzing current-day familial data.

The "admixing" happened was thought to person happened much than 50,000 years ago, arsenic modern humans moved retired of Africa and apt crossed paths with some Neanderthals and Denisovans. But pinning down precisely wherever it happened has proven hard -- peculiarly successful the lawsuit of Denisovans.

Definitively Denisovan?

Any summation to the meager hominin fossil grounds of Asia is breathtaking news, said Katerina Douka, an adjunct prof of archaeological subject astatine the section of evolutionary anthropology astatine the University of Vienna. She wasn't progressive successful the research.

She said she would person liked to spot "more and extended evidence" that the bony was definitively Denisovan.

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"There is simply a concatenation of assumptions the authors judge successful bid to corroborate that this is simply a Denisovan fossil," she said.

"The world is that we cannot cognize whether this azygous and severely preserved molar belonged so to a Denisovan, a hybrid oregon adjacent an chartless hominin group. It mightiness good beryllium a Denisovan, and I would emotion it to beryllium a Denisovan, due to the fact that however chill would that be? But much assured grounds is needed," she said.

In deeming the Laos bony Denisovan, the researchers successful this survey relied heavy connected a examination with the Xiahe jawbone, Douka said. However, the jawbone, portion thought by galore to beryllium Denisovan, was not an open-and-shut case. No DNA had been retrieved from the fossilized jawbone, lone "thin" macromolecule evidence, she added.

"Anyone moving connected this hominin group, wherever galore large questions inactive remain, wants to adhd caller dots connected the map. The trouble is successful reliably identifying immoderate fossils arsenic that of a Denisovan," she said. "This deficiency of robust biomolecular data, however, reduces importantly the interaction of this caller find and it is simply a reminder of however hard it is to enactment successful the tropics."

The survey authors said they planned to effort and extract past DNA from the tooth, which, if possible, would supply a much definitive reply but the lukewarm clime means that could beryllium a agelong shot. The probe squad besides plans to proceed excavating the tract aft a pandemic-induced hiatus successful the anticipation of much discoveries of past humans that lived successful area.

"In this benignant of environment, DNA doesn't sphere good astatine each but we'll bash our best," said survey coauthor Fabrice Demeter, an adjunct prof astatine the Lundbeck Foundation GeoGenetics Centre successful Denmark.