The bone came from an ancient girl who was believed to be around 13-years-old when she died - approximately 90,000 years ago.

A bone fragment scarcely bigger than a quarter has provided archaeologists with their latest major scientific breakthrough.

A study published in Nature on August 22 analyzed the piece of bone and discovered that the ancient girl that the fragment belonged to was a never-before-discovered hybrid of two ancient human relatives: a Neanderthal and a Denisovan.

A group of Russian archaeologists originally came across the groundbreaking bone fragment in 2012 inside of the Denisova Cave in Siberia, according to a report released by the study’s authors. In their analysis, the researchers discovered that the bone belonged to a girl who died around 13-years-old nearly 90,000 years ago.

The bone was transferred to a group of researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. They sequenced the genome from the fragment and shockingly discovered that the girl’s mother was a Neanderthal and her father was a Denisovan.

Neanderthals and Denisovans inhabited Eurasia for thousands of years until around 40,000 years ago when they were replaced by modern humans. The Neanderthals primarily occupied the west and the Denisovans were found in the east.

Denisovans are a relatively new discovery as well. In 2010, a team of researchers discovered unusual hominin DNA from bone found in the Denisova cave in Siberia, according to National Geographic. They named the newly-discovered hominins Denisovan after the cave.

More research into the group showed that they were related to the Neanderthals, splitting off from them almost 400,000 years ago.

The two groups are the closest examples of extinct relatives of modern humans and were separated from each other more than 390,000 years ago, but just because they were separated doesn’t mean they never interacted.

“We knew from previous studies that Neanderthals and Denisovans must have occasionally had children together,” Viviane Slon, a researcher at the Max Planck Institute, said in a statement. “But I never thought we would be so lucky as to find an actual offspring of the two groups.”

In their study of the bone’s genome, the researchers were able to find out more than just who the girl’s parents were. They discovered that her Neanderthal mother was genetically more closely related to the Neanderthals who hailed from western Europe compared to the Neanderthals who lived in the Denisova cave.

In addition, they found that her Denisovan father also had at least one Neanderthal ancestor in his family tree, further confirming their previous theory that despite the separation of their groups, Neanderthals and Denisovans interacted quite frequently.

“Neanderthals and Denisovans may not have had many opportunities to meet,” Svante Pääbo, the director of the Department of Evolutionary Genetics at the Max Planck Institute and the lead author of the study, said. “But when they did, they must have mated frequently – much more so than we previously thought.”

This teenager’s 90,000-year-old bone is not just teaching us about the mating of our human ancestors – this fragment is helping mold our understanding of hominin interactions overall.

Next, find out what a 45,000-year-old bone reveals about Human-Neanderthal relations. After that, discover who wrote the Bible according to actual historical evidence.