Scientists have found traces of a long, lost human cousin while looking at the genetic make-up of people from South Pacific islands, also known as Melanesia.
Until now, the evidence in fossils and DNA show that our ancestors were Neandertal or Denisovan hominids, but this study seems to reveal a third, unknown relative.
Ryan Bohlender, a statistical geneticist at the University of Texas MD Anderson Cancer Center, said the revelation means that ‘we’re missing a population or misunderstanding something about the relationships’.
Around 100,000 and 60,000 years ago, our early ancestors migrated from Africa and made contact with other hominid species living in Eurasia.
Neanderthals were a subspecies of humans that became extinct about 40,000 years ago, and Denisovans were only discovered in 2010 when a finger bone fragment was found in a remote cave in Siberia.
A new computer model can figure out how much Neandertal and Denisovan DNA is carried by modern humans.
European and Chinese people carry a similar amount of Neandertal DNA – about 2.8 per cent.
Hesman Saey explained to Science News:
Europeans have no hint of Denisovan ancestry, and people in China have a tiny amount – 0.1 percent, according to Bohlender’s calculations. But 2.74 percent of the DNA in people in Papua New Guinea comes from Neandertals.
And Bohlender estimates the amount of Denisovan DNA in Melanesians is about 1.11 percent, not the 3 to 6 percent estimated by other researchers.
While investigating the Denisovan discrepancy, Bohlender and colleagues came to the conclusion that a third group of hominids may have bred with the ancestors of Melanesians.”
Human history is a lot more complicated than we thought it was.
Other scientists make the point that researchers know very little about the genetic make up of Denisovans, due to there being so few fossils to analyse.
It is possible that Denisovans differed more than we realise, and this new DNA is variant of them.
Jakobsson says he would not be surprised if there were other groups of extinct hominids because ‘modern humans and archaic humans have met many times and had children together’.