Researchers found that the ancestors of East Asians may have interbred with an ancient population of Denisovans-archaic humans, cavemen, named for the Denisova Cave in Siberia where their remains were discovered.

Previous studies suggest that there were two separate interbreeding events between archaic humans and modern day human ancestors after the emergence from Africa.

One event involving Neanderthals, an extinct human species that was widely distributed in ice age Europe, gave rise to modern non-African populations and another event involving Denisovans, members of the genus Homo that are believed to belong to a previously unknown species, gave rise to present day Oceanians.

In other words, researchers have found that present day East Asians carry a trace of ancient history in their DNA their genetic ancestors included that of early man Denisovans.

Researcher Mattias Jakobsson compared genetic data from more than 1,500 modern day humans from around the world with the recently decoded genomes of a Neanderthal and a Denisovan to search for additional geographic patterns of archaic human ancestry.

Researchers found that, Southeast Asians, like Oceanians, have a high frequency of Denisovan-related genetic signatures, which are uncommon in other modern human populations, including Europeans, Americans, and West/Central Asians.

After comparing three computer models of human expansion out of Africa, they suggest that Denisovan ancestry in Southeast Asians is best explained by interbreeding between Denisovans and the ancestors of modern-day mainland East Asians.

“These results suggest admixture between Denisovans or a Denisova-related population and the ancestors of East Asians, and that the history of anatomically modern and archaic humans might be more complex than previously proposed,” the author wrote.