Relationships are complex – and none more so than the sex-laced, migratory mystery of Neanderthals and modern humans.
A startling new discovery begins with a Neanderthal femur bone found 80 years ago and ends with a change to the timeline of human history, published today in the journal Nature Communications.
A 124,000-year-old Neanderthal fossil found in Germany has turned up modern human DNA. This suggests that hominin migration out of Africa occurred much earlier than expected – more than 270,000 years ago.
The story as we previously knew it went as follows: The common ancestor of modern humans, Neanderthals, and Denisovans lived between 765,000 and 550,000 years ago. While modern humans remained in Africa until about 60,000 years, Neanderthals and Denisovans spread throughout Eurasia. Breeding between humans and Neanderthals became more common roughly 50,000 years ago.
This, however, seems to be incorrect. It turns out that some Homo sapiens (or close relatives of them) walked out of Africa more than 270,000 years ago and subsequently interbred with Neanderthals in Europe. It’s likely that these ancient migrants then vanished from the fossil record for some reason or another, but not before their genetic legacy left an imprint on generations of Neanderthals to come.
This is a huge discovery. Paleontologists have struggled for decades to reconcile piecemeal fossil data into a coherent timeline of ancient human history.
"We are realizing more and more that the evolutionary history of modern and archaic humans was a lot more reticulated than we would have thought 10 years ago," co-author Fernando Racimo of the New York Genome Center told New Scientist. "This and previous findings are lending support to models with frequent interbreeding events."
The current evidence comes from the mitochondrial DNA (mtDNA) of a Neanderthal femur bone discovered in 1937 near the entrance of Hohlenstein-Stadel cave in southwest Germany.