• Our human evolutionary lineage includes many species and relatives, including Neanderthals and Denisovans.
  • Scientists already knew that modern humans interbred with Neanderthals and Denisovans 40,000 to 60,000 years ago.
  • But a new study showed that the ancestors of Neanderthals and Denisovans also interbred with a mysterious population of ancient humans in Eurasia much earlier: 700,000 years ago. 
  • It’s the earliest known example of mating between different human populations. 
  • Visit Business Insider’s homepage for more stories.

Our evolutionary history is full of interspecies sex.

Different human ancestor species seem to have mingled and mated far more than anthropologists previously realized. Neanderthals interbred with modern humans. Homo sapiens had sex with Denisovans. And 700,000 years ago, according to a new study, a population of ancient humans mated with a distinct unknown population that had separated from other human species at least 1 million years prior.

“This continues the story that we’ve been seeing in studies throughout the past decade: There’s lots more interbreeding between lots of human populations than we were aware of ever before,” Alan Rogers, an anthropologist and the lead author of the new study, told Business Insider. “This discovery has pushed the time depth of those interbreedings much further back.”

According to his team’s research, published today in the journal Science Advances, the newly discovered interbreeding event took place in Eurasia, and it represents the earliest known example of mating between different populations of ancient humans.  

The analysis, which compared DNA from Neanderthals, Denisovans, and modern humans from Europe and Africa, lends further credence to the idea that our ancestors’ genes (and our own) came from myriad sources.

The oldest episode of interbreeding in the anthropological record

When geneticists finished sequencing the Neanderthal genome in 2010, they realized that Neanderthals had interbred with modern humans between 40,000 and 60,000 years ago. Then a 2018 study showed that Denisovans — which disappeared about 50,000 years ago — passed on some of their genes to Homo sapiens.

The artistic rendering of the head and face of a 13-year-old girl from the the prehistoric human species, Denisovan, based on technology developed by Hebrew University professor Liran Carmel and his team, is revealed at a news conference in Jerusalem September 19, 2src19. REUTERS/Ammar Awad

An artistic rendering of the head and face of a 13-year-old girl from the human ancestor species Denisovans.

Ammar Awad/Reuters

But the interbreeding event that Rogers and his colleagues found was far, far older. In that case, a group of humans who were ancestors of both Neanderthals and Denisovans

Read More