David Reich

And marine stage two, four, six, eight, and so on are the ice ages.

So the last glacial maximum was marine isotope stage two.

I think we would.

I think nobody has found... I mean, there's very sophisticated human burials in Europe and Africa and East Asia and different parts of South Asia and Eurasia and so on.

Australia in the last, you know, in the marine isotope stage three, in the last period of warming.

And...

you know, burials full of beads, burials full of symbolic behavior.

Maybe you interpret this as civilization, but extensive settled societies you don't see.

The entire human lineage is... I think that the sort of lesson from ancient DNA and the genome revolution has been that anyone in the world is the result of recurrent mixture again and again in the past.

So you might think that the last 500 years are unusual periods of history with the people of African and European and

Native American ancestry coming together in the Americas, and that this is unusual because of transatlantic travel, but almost every group in the world is the result of many mixture events as profound as these on many timescales.

So South Asians are the result of mixture between groups very different from each other, as different as Europeans and East Asians.

four to three to 2,000 years ago, coming together and then crystallizing into a relative lack of mixture.

Since that time, Europeans are the result of mixture of Yamnaya and farmers and hunter-gatherers.

People in different Near Eastern groups are the mixture of kind of early Iranians and early Levantine people and Anatolians who are super different from each other.

There's huge differences amongst East Asians, huge differences amongst Papuans and East Asians, profound differences amongst different Native American groups that come together to form groups that we have data from later in example after example we look for.

So if you think about any one lineage today, any one group of people, and you want to trace people's ancestors back in time and think, where do our ancestors scatter in geography at different time points?

Almost everybody's ancestors are scattered into...

different geographic distributions that are not all in the same place.

So the evidence that our lineage was mostly in Africa is based on an idea, I think, an assumption, a kind of inertial idea that our lineage must have always been in Africa because Africa is the center of human history.