New research suggests that early humans mated with both Neanderthals as well as Denisovans, a recently-discovered early human species.
Genomes from Denisovans, a third early human species, were originally traced to the people of Oceania, but further investigation reveals that genomes can also be found among East Asia populations, the Telegraph reports.
LiveScience explains the relation:
The Denisovans likely split off from the Neanderthal branch of the hominin family tree about 300,000 years ago, but little else is known about their appearance, behavior or dress.
Researchers also have found "genetic echoes of the Denisovans in modern residents of Pacific islands."
National Geographic writes that according to the study, "About one percent of the genetic makeup of people from southern China and the surrounding region comes from ... Denisovans."
Results from the study were published in the "Proceedings of the National Academy of Sciences" on Oct. 31.
Mattias Jakobsson, a professor of evolutionary biology at Uppsala University in Sweden, estimates that the human and Denisovan interbreeding took places between 23,000 to 45,000 years ago, LiveScience points out.
"We were evolving for a little while, then isolated, then mixed again," Jakobsson said, according to Wired Science.
Denisovans were previously unknown until 2010, after scientists declared fossils (part of a finger and a tooth) they had uncovered in 2008 belonged to a "distinct population of humans," with DNA sequences similar to Neanderthals', according to Wired.