IT GOES to the heart of who we are and where we came from. Our human ancestors were still interbreeding with their chimp cousins long after first splitting from the chimpanzee lineage, a genetic study suggests. Early humans and chimps may even have hybridised completely before diverging a second time. If so, some of the earliest fossils of proto-humans might represent an abortive first attempt to diverge from chimps, rather than being our direct ancestors.
We can observe the traces of this complex history in the human genome today, says David Reich, a population geneticist at the Broad Institute and…
