Meet Denny: The First Known Hybrid Offspring of Two Different Human Species

More than 50,000 years ago, the first human hybrid walked the Earth. This unique child is the only known individual whose parents were from two different human species.

(Photo: Wikimedia Commons/ Jakub Hałun)

Interspecies Love Child

In 2012, Russian archaeologists were exploring the Denisova Cave in the Altai Mountains of Siberia when they encountered a bone fragment. Samantha Brown from the University of Oxford led a team of scientists who examined the proteins preserved inside it.

DNA analysis of the remains revealed that the bones belonged to a teenage girl who was about 13 years old at the time of death. She was named "Denisova 11," or Denny for short.

The researchers also discovered that Denny had a unique parentage. DNA analysis of a small fragment of bone has revealed that the child was not Homo sapiens. Instead, she was the product of the sexual liaison between two human species.

A person's DNA comes in paired strands called chromosomes, one from each parent. In Denny's case, each pair had one Neanderthal and one Denisovan chromosome, with minimal mixing.

When the results came out, paleogeneticist Viviane Slon from the Max Planck Institute for Evolutionary Anthropology did not believe it. She thought there was a mistake or the sample might be contaminated. She then decided to sample the bone from another spot but got the same result. After running tests on six samples, the results were the same.

The discovery of Denny suggests that there was far more crossover between the branches of our early hominid ancestors than initially thought. Denny's bones are a first-generation human hybrid's only known physical remains.

Relatives of Modern Human

There are 23 ancient hominins whose genomes were sequenced, and Denny is not the only one with shared ancestry. There is also "Oase 1", a member of the modern species who lived 37,000 years ago in modern-day Romania. Oase 1 had a Neanderthal ancestor just four to six generations earlier.

Denisovans are an ancient group of archaic humans who emerged about 370,000 years ago during the Pleistocene Epoch in Eurasia. They are a relatively recent and mysterious addition to the human family tree. They were discovered in 2010 when an international team of scientists found an unusual hominin DNA from a pinky bone and wisdom tooth in the Denisova cave.

Thousands of years ago, the two groups were known to have lived on the continent of Eurasia, with Neanderthals thriving in the west and Denisovans in the east. According to Svante Pääbo from the Max Planck Institute, Neanderthals and Denisovans may not have had many opportunities to meet. But when they did, they must have mated frequently, even more so than previously thought.

Researchers had long suspected that these two groups of human species interbred since they left their genes in ancient and modern human genomes. Until the discovery of Denny, no one had ever found the direct offspring from such a pairing.

Both Neanderthal and Denisovan genes still exist in modern humans' DNA. In fact, the DNA of 2% of most European and Asian populations is Neanderthal in nature, while 4-6% of modern Melanesian DNA has traces from Denisovans.