One of the features that distinguish modern humans (right) from Neandertals (left) is a globular shape of the braincase.​

This “ archaic ghost population ” appears to have diverged from modern humans before Neanderthals split off from the family tree, according to the research published by the “ Science Advances ” journal.

The split appeared to have taken place between 360,000 and a million years ago, say the researchers from the University of California, Los Angeles. These ancient humans had babies with the ancestors of present-day Africans, much as Neanderthals reproduced with the ancestors of modern Europeans, wrote geneticists Arun Durvasula and Sriram Sankararaman.

DNA from this archaic population makes up between 2% and 19% of modern West Africans’ genetic ancestry, they said.