In 1989, a femur and part of a skull were found in a cave in China’s Yunnan Province in the southwestern region of the country.
Radiocarbon dating conducted in 2008 on the sediments where the fossils were found suggests they are about 14,000 years old – which means it was from a period of time when Homo sapiens (modern humans) migrated to many parts of the world.
However, the primitive features of the bones bothered scientists, who wondered what kind of human the fossils belonged to.
The shape of the skull resembles that of Neanderthals – an ancient human group that disappeared about 40,000 years ago – and it appears that the brain would have been smaller than that of modern humans.
As a result, some experts in human evolution have thought that the skull may have belonged to a hybrid group of ancient and modern humans or perhaps a previously unknown human species that coexisted alongside our own. Researchers gave the group the name Red Deer People after the name of the cave where the remains were found.
Now, Chinese scientists have extracted genetic material from the skull cap and sequenced the DNA. They found that the skull belonged to a female, which was most likely a direct ancestor of humans – a member of Homo sapiens. sapiens – not a previously unknown type of human being.
“Ancient DNA technology is a really powerful tool,” said Ping Su, a professor at the Kunming Institute of Zoology. at the Chinese Academy of Sciences in Yunnan who participated in the research, in a press release. “It tells us conclusively that the people in Red Deer Cave were modern humans rather than an ancient species, such as Neanderthals or Denisovans, despite their unusual morphological features.”
Su and colleagues share their findings in a study published Thursday in the journal Current Biology. Their analysis of the genome revealed which individual the bones belonged to They had levels of Neanderthal and Denisovan ancestry that were similar to those of modern humans – indicating that they were not part of a hybrid group that interbred with each other.
DNA from Denisovans, a little understood group of ancient humans, and Neanderthals live in some humans today. This is because long ago our ancestors Homo sapiens encountered these groups as they spread around the world and breed with them.
The first Americans?
The researchers compared the genomes extracted from ancient DNA with the genomes of other people from around the world – both modern and ancient.
They found that the bones belonged to an individual who was closely related to Native American ancestry in East Asia. Researchers believe that this group of people traveled north to Siberia and then crossed the Bering Strait to become some of the first Americans.
“Its genome fills in a really important missing part of the overall story of how humans got to the Americas. Much of the work has focused on the other branch of Native American ancestry – the Siberians – but little was known until this paper about the ancestors of the Native Americans in East Asia. It is really important Understand this branch, because it represents the majority of Native American ancestry!” Jennifer Ruff, a geneticist and anthropologist at the University of Kansas and author of “Origin: A Genetic History of the Americas,” said via email.
Added Raff, who was not involved in the research.
Rugged features
But what explains the unusual morphological features of the remains?
The researchers described the genome as having “low coverage”, which means it does not contain enough detail to provide an explanation for why bones are different from Modern human skeletons. The acidic soil and warm, humid conditions where the skull was found meant that scientists were only able to recover 11.3% of the genome. This was the first time that DNA had been sequenced from a human fossil found in southern China.
The study indicated that the individual to whom the bones belong It had a lot of genetic diversity, suggesting that a number of different lineages of early modern humans must have coexisted in Southeast Asia during the Late Stone Age. The study suggested, perhaps, the area was a refuge during the height of the Ice Age.
“I know these fossils better than anyone else,” Cornu, who was not involved in the latest study, said by email. “They are very anatomically puzzling, even if they are modern humans, as the DNA suggests.”
“How do we reconcile that? Perhaps the anatomical shape of people in the past – over long periods of time – was very flexible and responded to the environment and lifestyle of these early people. This may be something we have lost since we started farming.”
Analysis of the Red Deer Cave’s genome could also help build a more complete picture of ancient humans in East and Southeast Asia – an exciting place for paleontologists.
Next, the Chinese team hopes to find additional support for its findings by sequencing ancient human DNA using fossils from Southeast Asia, particularly those that predate the red deer cave people.