A study has made a startling claim. It argues that an extinct species of humans, the Denisovans, may have mated with modern humans ( Homo sapiens ) as late as 15,000 years ago. This claim is based on the genetic analysis of Papuans’ DNA and could transform our understanding of the evolution of modern humans. It seems that the Denisovans survived until relatively recent times, and that they mated with Homo sapiens for thousands of years.

The Denisovans ( Homo denisova ) were hominids related to the Neanderthals, but the two species diverged about three quarters of a million years ago. All that is known about them comes from a single cave in Siberia, the Denisova cave . Recently archaeologists uncovered “two pieces of a Denisovan skull” in the cave, reports Ancient Origins . These hunks of a skull are so prized because the remains of only five Homo denisova have ever been found.

Denisova cave. (loronet / CC BY-SA 2.0 )

Genetic Legacy of Denisovans

Geneticists have been able to identify their DNA and this is helping us to better understand this extinct species of humans. Researchers had been able to establish their genetic legacy in a population ranging from “the Philippines and New Guinea to China and Tibet have inherited 3% to 5% of their DNA from Denisovans” reports the Science Mag .

It seems that this branch of the human family left Africa sometime before Homo sapiens and that they lived in Asia for thousands of years. When modern humans entered Asia some 50,000 years ago, members of the two species mated with each other. The Science Mag reports that as a result of this extensive interbreeding many modern Melanesian populations in the Pacific have up to “3% to 5% of their DNA from them.”

A team of biologists led by Murray Cox and Herawati Sudoyo found traces of two types of DNA from Denisovan populations in samples of Papuans from New Guinea. After studying the results using statistical analysis they found that some of the genes had only entered the human genome as late as 15,000 years ago. Finding Denisovan genetic material at so late a date was very exciting. The genetic analysis of the sample from New Guinea adds to the body of evidence for mating between modern humans and the Denisovans.

A study of the DNA of Papuans from New Guinea led to the discovery that Denisovans and modern humans mated. (Flickr upload bot / CC BY-SA 2.0 )

Modern Humans and Denisovan Mating

Evidence for interbreeding could help us to understand how the Denisovans became extinct. It appears that they were not driven to extinction by the activities of early modern humans, as some have suggested. To put it simply the extinct species bred with early humans and became over time indistinguishable from them. According to the National Geographic , the evidence “indicates their numbers were never very high.” Such a small group could have easily been subsumed into the larger Homo sapiens population by interbreeding.

The findings of the team led by Cox and Sudoyo have lent support to the view that the Denisovans were much more widespread at a later date than previously thought. It seems that their DNA entered the human genome some 30-15,000 years ago. This indicates that members of the species were apparently living in New Guinea at this date along with Homo sapiens .

The Last Denisovans?

This possibly indicates that isolated populations of Denisovans survived as late as 15,000 years ago in the Pacific Islands . The Science Mag quotes Christ Stringer of the London Natural History Museum as stating that a “late surviving lineage [of Denisovans] could have interbred with Homo sapiens .” Moreover, it suggests that modern humans and the extinct species were mating over a period of tens of thousands of years.

There are those who reject this and, while accepting that while Homo sapiens and Homo denisova may have mated regularly, claim it is highly unlikely that they did so as recently as 15,000 years ago. The discovery may be accounted for by two groups who had been isolated from each other and who both had some Denisovan DNA. Because of migrations they encountered each other after a long period of time and mated and this could explain the findings of the international team of biologists.

DNA evidence concludes that Denisovans mated with modern humans as late as 15,000 years ago. ( vectorfusionart / Adobe)

The evidence from New Guinea is adding to our understanding of the long-extinct species. They were a diverse population that appears to have interbred with modern humans for an extended period. This is changing how we see modern people and how they came to dominate the world, they may have peacefully absorbed groups like the Denisovans by interbreeding. This could also explain why Homo sapiens are the only surviving human species .

Top image: Denisovans mated with modern humans. Source: Kovalenko I / Adobe .

By Ed Whelan