The ancestors of all modern humans split off from a mystery population 1.5 million years ago and then reconnected with them 300,000 years ago, a new genetic model suggests. The unknown population contributed 20% of our DNA and may have boosted humans' brain function.
"The fact that we can reconstruct events from hundreds of thousands or millions of years ago just by looking at DNA today is astonishing, and it tells us that our history is far richer and more complex than we imagined," study co-author Aylwyn Scally, a geneticist at the University of Cambridge, said in a statement.
