DNA From Huge Ancient Tooth Unearths Our New Cousin — And We Have No Clue Who He Is

In the ancient world, humans were far from the only people on the block. We lived alongside Neanderthals, likely other as-yet undiscovered hominids, and thanks to clues left in the DNA of a very old tooth, a mysterious people called the Denisovans.

All that is left of the Denisovans is a finger bone and two fossil wisdom teeth. One tooth was found in 2010 with the finger bone and the other later that year. Early humans lived beside Neanderthals for hundreds of thousands of years until they vanished 40,000 years ago, and the DNA from these molars suggests other ancient people were around at that time, too, National Geographic reported.

And more Denisovans may be hiding in plain sight, disguised in museums– for now — as humans or Homo erectus.

The fossil was found in a Siberian cave called the Denisova cave (hence the name given these ancient peoples), located in the Altai Mountains, and a place where a variety of ancient humans have been found.

“It’s an amazing place because it’s actually the only place in the world where we know that three different groups of humans with very different histories all lived,” said Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology.

When they unearthed the tooth and finger bone back in 2010, a team of geneticists and anthropologists discovered it had some strange DNA. It was also odd to look at — incredibly large for a hominid tooth, with massive splayed roots that must have belonged to someone with a massive jaw, Popular Science noted.

DNA from the first discovery was examined and told scientists that the Denisovans — whoever they were — contributed 5 percent of the genome of the people who now live in Papua New Guinea and other parts of the Pacific.

Then, later in 2010, researchers were fishing around the deepest recesses of the Siberian cave when they found something else — another ancient wisdom tooth. DNA analysis fell to anthropologist Bence Viola, who first thought it was the molar of a cave bear.

Of course, it wasn’t, rather the massive chomper of a Denisovan. Viola compared the two teeth and discovered that they were quite similar to each other and distinct from humans and Neanderthals.

DNA analysis also pinned down the date the Denisovans with the massive teeth lived. The person who owned the second tooth lived 60,000 years after the person who left behind his tooth and finger bone — much earlier than previously thought. This suggests that these people were part of one biological group that lived in that region of Siberia as long as humans.

“The world at that time must have been far more complex than previously thought,” said Susanna Sawyer, who studied the tooth. “Who knows what other hominids lived and what effects they had on us?”

Despite learning quite a bit about the ancient people’s DNA, which shows that they had as much genetic diversity as modern Europeans and much more than Neanderthals, scientists know next to nothing about how these ancient people looked or behaved beyond the assumption that they had to be quite hardy to survive Siberia’s harsh climate.

Among their questions: Where else did they live? What other hominid species did they breed with? How did they behave? What did they look like? Scientists may find answers if they discover more ancient remains, or if they figure out that some bones in museums around the world are Denisovans masquerading as other hominids.

For now, the DNA in two teeth and one finger bone are all that science has to study, and to Sawyer, that’s pretty cool.

“It feels a bit surreal. Sometimes when I’m sitting in the clean room, I stop to think about how crazy it is that I am holding one of the only remains known to date from a new and mysterious hominid group.”

[Image via Shutterstock]