Scientists unearth evidence of ancient human "ghost population"
Computer scans of modern human genomes reveal genes from a long-lost population of unknown prehistoric humans.
By Dorthy Ziemann | Feb 20, 2020 | Print-friendly

An unknown ancient population of early humans that vanished without leaving any traceable fossils may be the source of some of our present-day DNA, according to California geologists. The geologists, using software analyses of human genomes, have identified much of modern west African humans' genes as coming from a "ghost population" that lived in western Africa around 500,000 years ago.

This ghost population would have mingled and bred with other human populations and given rise to the hominids that became the modern humans of western Africa, the geologists suggest. They compare it to similar hypothesized interbreeding that may have occurred among Neanderthals and ancient hominids in Europe tens of thousands of years ago.

The researchers analyzed genomes of present-day west Africans and found that as much as a fifth of their DNA may have come from this ghost populations. There were no traceable fossils to study, but the researchers traced the population from gene sequences that appeared in the modern-day genomes and differed from modern genes.

"In the west Africans we looked at, all have ancestry from this unknown archaic population," said Sriram Sankararaman, a computational biologist who led the research at the University of California in Los Angeles. "They seem to have made a pretty substantial impact on the genomes of the present day individuals we studied."

Sankararaman and colleagues think that this ghost population split from ancestors of Neanderthals and modern humans between 1 million and 360,000 years ago. Then around 124,000 years ago, this population bred with the ancestors of modern west Africans.