Scientists discover evidence of new ancient human species

  • Scientists discover evidence of new ancient human species

Scientists discover evidence of new ancient human species

"It's an exciting moment because these studies open a window showing us that there is much more than we thought to learn about our ancestors".

Sankararaman and Durvasula estimate that the ghost species split between 1 million and 360,000 years ago from the lineage that produced modern humans and Neanderthals, and that members of that species interbred with Homo sapiens sometime in the past 124,000 years. And there's plenty of evidence from other parts of the world that early humans had sex with other hominins, like Neanderthals.

Evidence of the 'ghost population' appeared when scientists studied genomes from west African populations and discovered that about a fifth of their DNA seemed to have originated from the missing group.

According to their research, the "ghost population" of ancestors may have mated with ancestors of people living in what is today West Africa, and that would explain the genetic diversity within modern West African populations.

Sriram Sankararaman, a computational biologist at UCLA and one of the study's authors, said: 'It's nearly certainly the case that the story is incredibly complex and complicated and we have kind of these initial hints about the complexity'. Therefore, modern Europeans have a handful of Neanderthal genes, while indigenous Australians, Polynesians, and Melanesians carry genomes from Denisovans, another species of ancient humans. And when they stumbled upon one another, mating was not out of the question.

By employing statistical techniques, the researchers looked for markers of interbreeding that may have occurred in the distant past - turns out it did. But while there is an ample fossil record of the Neanderthals and a few fossils of Denisovans, the newly identified "ghost population" is more enigmatic.

They discovered signals of what they have termed "ghost DNA", which they believe comes from a group of humans that were previously unknown. More information is required by the researchers to believe that the ghost population descends from the ancestors of Neanderthals.

Last month, researchers from Princeton's Lewis-Sigler Institute for Integrative Genomics said they also detected Neanderthal ancestry in Africans for the first time.

We don't know how these human relatives looked like or how they lived, but their genes paint a compelling story of complex interactions with our ancestors.

The researchers are now keen to delve into the ancient genes and work out what they do. One possibility is that west Africans retained the DNA because it helped them to survive and breed.

"Actually knowing who those ancestors were, how they interacted, and where they existed is going to take fieldwork to find their fossil and archaeological remains", he told the Guardian. "That tells us that these archaic populations might have had some DNA that did some useful stuff that's proved to be useful to the modern population", she says. It is tempting to speculate. "We haven't discovered enough fossils in most of Africa to say we know what was there".