Dwarkesh Patel

As you said, across trade after trade, the selection intensifies during the Bronze Age.

And this makes sense for some things.

For example, why do we see lactase persistence where adults can process milk?

Why is that intensified during this period?

Oh, well, it makes sense.

This is the time when we start using cattle, not just for the meat, but then also for milk and wool and other secondary products.

So it makes sense this is why lactase persistence would matter more.

But then there's other things which seem like they should have been relevant since the dawn of agriculture.

I forget the exact name of the allele, but was it FADS1?

Yeah.

Which helps convert plant fatty acids into long-chain fatty acids that your body needs.

And that's obviously relevant when you move from a diet of meat as a hunter-gatherer to a diet of cereals.

But that is also one I think you found was under a special selection, or especially high selection, 5,000, 3,000 years ago.

Yeah, so what's going on?

Why is the bronze age so special across all these different traits that you're observing?

So you did some work with Bhatia and many other colleagues in 2014.

You were looking at 20 or 30,000 African-American genomes today, and you were saying, look, there's some percentage, 80% West African DNA and then 20% European DNA.

And can we look at their

uh genomes today and do we see that their uh allele frequencies are much different than what you just expect from this ad mixture um and you find correct me if i'm wrong but you found that they weren't that is to say that over 200 300 years of extremely

intense environment change, you know, going from, you know, yeah, chattel slavery and, yeah, completely new environment.