Again, after 9,000 years ago, there’s a mass movement of farmers into the region which almost completely replaces the hunter-gatherers with a small amount of mixture.

And then again, after 5,000 years ago, there’s this mass movement at the beginning of the Bronze Age of people from the steppe, who also probably bring these languages that are spoken by the great majority of Europeans today.

So in regard to Cheddar Man, he is from one of these groups that repeopled northern Europe from the south after the Ice Age. And this group was characterized by ancestry related to southeast Europeans. They did not have a lot of the skin-lightening mutations that are present in the first farmers and even more in the steppe pastoralists who come later. They don’t have the blond hair that is characteristic of many northern Europeans today. They do have the blue eyes that are characteristic of this region today. So you have this unusual look of dark skin and blue eyes.

Zhang: You’ve said that ancient DNA has changed the way we see archaeology from these time periods. How so?

Reich: Archaeology has always been political, especially in Europe. Archaeologists are very aware of the misuse of archaeology in the past, in the 20th century. There’s a very famous German archaeologist named Gustaf Kossinna, who was the first or one of the first to come up with the idea of “material culture.” Say, you see similar pots, and therefore you’re in a region where there was shared community and aspects of culture.

He went so far as to argue that when you see the spread of these pots, you’re actually seeing a spread of people and there’s a one-to-one mapping for those things. His ideas were used by the Nazis later, in propaganda, to argue that a particular group in Europe, the Aryans, expanded in all directions across Europe. He believed that the region where these people’s material culture was located is the natural homeland of the Aryan community, and the Germans were the natural inheritors of that. This was used to justify their expansionism in the propaganda that the Germans used in the run-up to the Second World War.

So after the Second World War, there was a very strong reaction in the European archaeological community—not just the Germans, but the broad continental European archaeological community—to the fact that their discipline had been used for these terrible political ends. And there was a retreat from the ideas of Kossinna.

Zhang: You actually had German collaborators drop out of a study because of these exact concerns, right? One of them wrote, “We must(!) avoid ... being compared with the so-called ‘siedlungsarchäologie Method’ from Gustaf Kossinna!”

Reich: Yeah, that’s right. I think one of the things the ancient DNA is showing is actually the Corded Ware culture does correspond coherently to a group of people. [Editor’s note: The Corded Ware made pottery with cord-like ornamentation and according to ancient DNA studies, they descended from steppe ancestry.] I think that was a very sensitive issue to some of our coauthors, and one of the coauthors resigned because he felt we were returning to that idea of migration in archaeology that pots are the same as people. There have been a fair number of other coauthors from different parts of continental Europe who shared this anxiety.