By John Timmer
By now, it’s pretty firmly established that modern humans interbred with Neanderthals when our ancestors reached Eurasia. What’s less clear is when (and how often) this happened. Estimates of the event have wide error ranges, covering the entire time from when modern humans left Africa to the disappearance of Neanderthals from the fossil record.
Now, human remains have yielded DNA that may indicate at least two distinct Neanderthal interbreeding events, one of them only a few generations earlier. The only problem? There’s no indication that this skeleton’s population contributed to any current group of humans.
The best evidence we have on the timing of interbreeding comes from a modern human skeleton from Siberia that dates from about 45,000 years ago. That suggests that interbreeding with Neanderthals took place about 60,000 years ago, which would place it at a time when modern humans were first reaching the Middle East. But there were some hints that additional Neanderthal DNA came into that lineage more recently.