Charles Darwin in his seminal book On the Origin of Species had first hinted at the possibility of humans having evolved from a common ancestor. However, the story of human evolution is not a straight forward affair. Genes from fossilized remains have hinted that human ancestors may have lived and mated with Neanderthals and another mysterious species of ancient extinct humans from Asia, called the Denisovans.
According to a latest report in Science Mag, new studies suggest that ancestors of all three ancient groups mixed at least twice with an even older 'ghost' lineage of extinct hominins.
As per the study, even before modern humans migrated out of Africa, it was common for different human ancestors to mingle and procreate. The report quoted computational biologist Murray Cox of Massey University of New Zealand, as saying that the study now makes it clear that the interbreeding between different groups of humans goes a long way back. Cox was, however, not involved in the study.
Science Mag cited journal Science Advances where it was revealed that population geneticist from the University of Utah, Salt Lake City, Alan Rogers, along with his team identified variations in genomes of different human populations. These included Europeans, Asians, Neanderthals, and Denisovans.
They tested eight scenarios of how genes are distributed, coming to the conclusion that the ancestors of Neanderthals and Denisovans—whom they call Neandersovans—interbred with a “super-archaic” population that parted from other humans about 2 million years ago. They further added that the mixing likely happened outside of Africa, because that’s where both Neanderthals and Denisovans emerged.
The study reveals that at least two super-archaic extinct hominins interbred with ancestors of Neanderthals, Denisovans and modern humans, who later intermingled leaving behind intricate genome traces in each other.