David Reich

By the time, you know, today, the most Yamnaya ancestry you see in India is 20% or 10.

You know, most people have less than 10% or 5%.

I see.

You know, there's just been a lot of mixture on the way, but it is the tracer dye, right?

Like it tracks Indo-European languages and important aspects of Indo-European culture are coming through Yamnaya.

So if you know where to look, that tracer dye is only 10%.

It's only 5%.

It's only 2% in some groups, but it's the languages people speak and it's important cultural shared elements that connect them to people on the other side of the Indo-European speaking world.

So this 5%, you shouldn't sneeze at it, right?

Like that's tracing something important in this model.

So the reason I'm talking about these matrilineal or patrilineal expansions is I'm really troubled and have been troubled for like many years, actually 15 years, but like especially in the last three or four years by the fact that the mitochondrial DNA and Y chromosome cluster Neanderthals in modern humans, but the rest of the genome clusters Neanderthals and Denisovans.

This is like a crazy result that is not seen in any other species where you see this pattern.

So I'm very interested in patterns that would explain this.

If you invoke and assume that there was like a matrilineal or a patrilineal expansion, it could be either, where modern humans, when they were expanded across the landscape of Europe, retained their identity along one of the lines.

Like if you incorporate a local, if it's matrilineal, when they incorporate a male from the local community, they're brought into the community and the kids are raised locally.

based on the culture of the mothers or something, or if it's a patrilineal expansion, they incorporate a female from the community.

It's incorporated sort of raised with the culture of the fathers.

So if that happens, it guarantees one of these two parts of the genome to look like it does, because it's a modern human expansion.

If it's patrilineal, it will retain the Y chromosome.

If it's matrilineal, it will retain the mitochondrial DNA.