I’ve mentioned from time to time that Neanderthals interbred with humans. The evidence shows that we have upwards of 4% of their DNA, depending on where our relatively recent ancestors lived. That is, people of European and Asian descent have a far higher chance of sharing DNA with our Neanderthals cousins than someone more recently from Africa. This is good evidence that we were not entirely separate species, but rather close branches on the evolutionary tree. However, new evidence suggests that our cousins weren’t at the right place at the right time for this to all make sense:
Previous dating of bone fossils found at Neanderthal sites in the region put the youngest at about 35,000 years.
But researchers from Australia and Europe re-examined the bones using an improved method to filter out contamination and concluded that the remains are about 50,000 years old.
If true, the study, casts doubt on the idea that modern humans and Neanderthals co-existed — and possibly even interbred — for millennia, because humans aren’t believed to have settled in the region until 42,000 years ago.
As always, absence of evidence is not necessarily evidence of absence. It’s still quite possible that Neanderthals hung around for another one or two thousand decades. Alternatively, humans may have arrived on the scene earlier than once thought. The problem is that we don’t have the fossil record to back any of that up.
The way I think the way this alters our view is not that it shows that Neanderthals and humans didn’t interbreed. Obviously for the above given reasons, that isn’t tenable. Instead, I think we have to revise a whole host of specifics; this is a quantitative problem, not a qualitative one.