David Reich

And so I'm very interested in this because

actually from the archeological record, Neanderthals and modern humans sort of look actually quite similar to each other, much more similar to each other than a lot of them do to Denisovans, these archaic humans in East Asia.

So a lot of the history, people have thought that Neanderthals are our sister, but in...

But in 2010, the sequencing of the Denisovan genome made it very clear that on average, Denisovans are closer to Neanderthals than to modern humans.

So this was like a very confusing result.

And most people now think that Neanderthals and Denisovans are like, descend from a common ancestral population, separated earlier from the ancestors of modern humans.

So I'm interested in the possibility that actually the right way to think about Neanderthals is actually as somehow culturally modern humans.

And even though that genetically they're mostly Denisovans.

And the model I'm thinking about is motivated by this archeological phenomenon known as the Middle Stone Age Revolution.

So if this is Africa and this is, I don't know, Europe,

We know that the new way of making stone tools with these cores that were very carefully mined far away from the locations they were used, made out of high quality stone like flint, start being used three or 400,000 years ago, first in the Caucasus, places like Georgia today or East Africa.

And that this way of making stone tools, which is quite revolutionary and is known in Europe as the Middle Paleolithic and Africa as the Middle Stone Age, and is associated with much more widespread use of fire and also moving stone around at much further distances than before,

I'm interested in the idea that this is something that's shared between modern humans and Neanderthals.

There's somehow some shared cultural feature that's absent in East Asia.

And that might have a relationship in the genetic data and is somehow related to this 5% DNA.

So the idea I'm interested in is the possibility that there is a population here that invents the Middle Stone Age and the Middle Paleolithic, sometimes called Levallois technology, and that people from this population expand into Europe.

and they mix with the local archaic humans who are there.

And that is what this 5% interbreeding event is.

It happens two to 300,000 years ago, and it produces a group that as it expands across this landscape in Europe, mostly picks up the local DNA and becomes mostly archaic genetically, but retains its modern human culture, the way of making stone tools and some of its traditions.

And so one of the things that's super interesting about this is that if you actually look