Ancient Humans Now Have a Face
Fifteen years ago, scientist Dr. Qiaomei Fu found a tiny piece of a finger bone in a Siberian cave called Denisova. At the time, she didn’t know what kind of human it came from. She thought it could have been from an early modern human or a Neanderthal. But Fu, a student in Germany at the time, and her team found DNA in the bone that revealed something interesting. The bone belonged to a girl from a completely different group of ancient humans. They named them the Denisovans.
Since then, Fu has found more Denisovan DNA in teeth, bones, cave dirt in Tibet, and even in modern people from Asia and the Pacific, showing they mixed with other humans long ago. Still, no one knew what Denisovans looked like because there were no full skeletons or skulls. Now, after 15 years, Fu says people are finally close to putting a face to the name.
Dr. Fu and her colleagues announced on Wednesday that a skull was found in China that contains Denisovan DNA and Denisovan protein. “This moment is special to me,” Dr. Fu said. This shows that they have discovered a huge part of their investigation. The discovery of the skull is even more special because it was almost lost forever. In 1933, a worker in Harbin, China, found it at a construction site. Thinking it might be important, he hid it in an old well but never came back for it. He didn’t tell anyone about it until just before he died. His family found the skull in 2018 and gave it to Hebei GEO University.
There, scientist Qiang Ji and his team studied the skull and found it was at least 146,000 years old, maybe even older. After rebuilding the face, they discovered it belonged to a large man with flat cheeks, a wide mouth, no chin, deep-set eyes under a heavy brow, and a big nose. His skull was huge, holding a brain about 7% larger than that of the average person today. Dr. Ji and his team decided the Harbin skull was so unique that it belonged to a new human species. In 2021, they named it Homo longi, after the region where it was found in. But some scientists, including Dr. Fu, thought it might actually be a Denisovan. She got permission to study the skull. Although she had previously searched many skulls in Chinese museums for Denisovan DNA, she had never found any.
To test examine the Harbin skull, Fu and her team took small samples from a tooth and a bone near the inner ear, which are the best places to find DNA. They didn’t find any ancient DNA, but they did find 95 proteins, a large amount for such an old fossil. This suggests that the skull was from a Denisovan. Even though that was an exciting discovery, Fu was disappointed they didn’t find DNA. DNA can tell scientists much more than proteins. So she tried one last thing, searching the plaque on the skull’s teeth. Plaque can trap bacteria and sometimes tiny bits of DNA from the mouth. She knew it was unlikely, but decided it was worth a try.
When Dr. Fu and her colleagues inspected a sample of the dental plaque, they discovered DNA. As expected, most of it came from bacteria. But a tiny part of it came from the mouth’s cells. And when they studied that DNA, they discovered that it was Denisovan.
In the end, Dr. Fu’s determination to uncover the truth about the Harbin skull paid off. Although she didn’t find DNA at first, the discovery of Denisovan proteins was a huge step in understanding our ancient relatives. Her work shows how even the smallest clues, like tooth plaque, can help solve big mysteries about human history. After years of searching, scientists are finally beginning to piece together what the Denisovans looked like.