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Identity of mysterious fossils found in Chinese cave revealed through DNA analysis

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In 1989, a femur and part of a skull were found in a cave in the Chinese province of Yunnan in the southwest of the country.

Radiocarbon dating done in 2008 on the deposits where the fossils were found showed them to be around 14,000 years old, meaning they date back to the time period when Homo sapiens (modern humans) migrated to many parts of the world.

However, the primitive features of the bones worried scientists, who wondered what kind of human the fossils belonged to.

The shape of the skull resembled that of Neanderthals – an archaic human population that disappeared about 40,000 years ago – and it seemed that the brain was smaller than that of modern humans.

As a result, some experts in human evolution believed that the skull probably belonged to a hybrid population of archaic and modern humans, or perhaps to a previously unknown human species that existed alongside our own. The researchers named the group the Red Deer People, after the cave where the remains were found.

Now Chinese scientists have extracted genetic material from the skull and sequenced the DNA. They found that the skull belonged to a woman who was most likely a direct human ancestor – a member of Homo. sapiens is a previously unknown type of human.

“The ancient DNA technique is really a powerful tool,” said Bing Su, a professor at the Kunming Institute of Zoology. at the Chinese Academy of Sciences in Yunnan, who participated in the study, in a press release. “This tells us quite definitely that the Red Deer Cave people were modern humans and not archaic species like Neanderthals or Denisovans, despite their unusual morphological features.”

Su and colleagues shared their findings in a study published Thursday in the journal Current Biology. Genome analysis revealed who owned the bones. had levels of Neanderthal and Denisovan ancestry that were similar to those found in modern humans, suggesting that they were not part of a hybrid population that interbred with each other.

The photo shows a skull found in the Red Deer Cave in Yunnan, China.

The DNA of Denisovans, a little-studied group of archaic humans, and Neanderthals lives on in some people today. This is because, long ago, our Homo sapiens ancestors encountered these groups as they spread across the world and bred with them.

First Americans?

The researchers compared the genome extracted from ancient DNA with the genomes of other people from all over the world – both modern and ancient.

They found that the bones belonged to a person who was closely related to the East Asian roots of the Native Americans. Researchers believe that this group of people traveled north to Siberia and then crossed the Bering Strait to become one of the first Americans.

“Her genome fills in a really important missing piece of the overall story of how humans got to America. A lot of work has been focused on another branch of Native American ancestry—the Siberians—but little has been known until this article on Native American ancestors from East Asia. It is very important to understand this branch, since it accounts for most of the ancestors of Native Americans!” said Jennifer Ruff, a geneticist and anthropologist at the University of Kansas and author of Origins: A Genetic History of America.

“I find their results plausible and very interesting. We are still trying to figure out the geographic location of the population directly ancestral to the first peoples, but this article gives us some additional clues,” added Ruff, who was not involved in the research. study.

This is an artist's representation of the red deer cave people who lived in Yunnan, China, about 14,000 years ago.

Reliable features

But what explained the unusual morphological features of the remains?

The researchers described the genome as “low coverage,” meaning it didn’t provide enough detail to explain why the bones looked different from bones. modern human skeletons. The acidic soil and warm, humid conditions in which the skull was found meant that scientists were only able to recover 11.3% of the genome. This was the first DNA sequencing of a human fossil found in southern China.

The study notes that the person who owned the bones had great genetic diversity, indicating that several different lineages of early modern humans must have coexisted in the Late Stone Age in southern East Asia. Perhaps, as the study showed, this region was a refuge at the height of the Ice Age.

Darren Cournot, a research fellow at the Australian Museums Research Institute in Sydney, said that in 2012 he published the first international scientific paper on fossils, which he says have “very complex anatomy”.
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“I know these fossils better than anyone else. Anatomically, they are very mysterious, even if they are modern humans, as DNA suggests,” Cournot, who was not involved in the latest study, said by email.

“How can we come to terms with this? Perhaps the anatomical form of people in the past – for a long time – was very “plastic” and reacted to the environment and lifestyle of these first people. It may be something we have lost since we started farming. .”

An analysis of the Red Deer Cave genome could also help build a more complete picture of ancient humans in East and Southeast Asia, an interesting place for paleoanthropologists.

It is here that some of the world’s oldest rock art has been discovered, as well as the remains of mysterious archaic people such as the Flores Hobbits in Indonesia and the Dragon Man in northern China. Other finds shed light on the enigmatic Denisovans.

The Chinese team then hopes to find additional support for their findings by sequencing more ancient human DNA using fossils from southern East Asia, especially those that predate the red deer cave dwellers.

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