"Today, I have the pleasure of speaking with  David Reich, who is a geneticist of ancient   DNA at Harvard. David's work, his lab's work  and his field's work, has really transformed   our understandin..."

"10 to 14 years, we collectively have been piecing  together an understanding of how modern humans are   related to our closest relatives, who are now no  longer with us in unmixed form: the Neandertha..."

"also learned this is true for the Y chromosome,  inherited from father to father. It too is only   maybe 300,000 or 400,000 years separated between  Neanderthals and modern humans. Like with the   mit..."

"modern humans and Neanderthals are just as  qualified to be sisters as Neanderthals and   Denisovans. In that case, maybe it's not clear  what's modern and what's archaic. Are modern   humans archaic?..."

"descended from Eurasia. Then you're saying  that 100,000 years before that is when we   have a sister lineage with Neanderthals.  On the new findings about how closely   related Neanderthals are to us..."

"Where did the most recent gene flow  between Neanderthals and humans happen? I   guess it’s not the most recent, because  the most recent was 60,000 or whatever   years ago. But the one you're referri..."

"where that occurred as I understand it. We're humans and you would think one of   the things history would have figured out is  how humans came to be. That's probably one of   the biggest questions yo..."

"The audience might not be aware of how much of a  change this is in our understanding of the human   past. I just really want to emphasize that. The gene flow event you're talking about a   few hundre..."

"again and again. I'm not an expert on this.  The simplest model would be one in which an   extension of the modern human substructure  leading to us—the ones that some of those   lineages coalesce to ..."

"interesting. A couple of years ago, we published  a paper on relatively recent hunter-gatherer   populations from mostly eastern and central  Africa in order to be able to discern these deep   populat..."

"There's some question about the migration rate  amongst these groups, an archipelago of little   groups losing diversity and going extinct  at some level. But together there is enough   recontact to r..."

"surprising how we came to be and how we are  through migrations and mixtures. A lot of   people used to think that we were not mixed. In  fact, it's been mixture again and again in the   past in many ..."

"I have so many questions there. When you  say that there's a single interconnected   population, are you referring not only to  basically all of Eurasia but also Africa?  Possibly. Basically the whole..."

"This is outside my area of expertise. I'm being  very much like a scientist right here. I'm very   sympathetic to the idea that it's hardly  genetic. I think that this is cultural   innovation. It's v..."

"based on epigenetic modification of  genomes. To explain what that means,   the genome is not just a sequence of DNA  letters, adenines, thymines, guanines, cytosines:   ACTG. It also is decorated in ..."

"To the extent that humans have had it for hundreds  of thousands of years, it's not clear then why   humans weren't able to expand out of Africa and… We don't know that. We just know that today   we h..."

"to see other people, to empathize with them, to  copy them, to incorporate bodies of information   learned by other people. I'm not an expert in this  topic, but it's a very appealing group of ideas. ..."

"One thing I didn't realize until I read your  book is how small the population that expanded   out into Eurasia was, and how small even generally  the human population was 50,000 to 100,000 years   ag..."

"mixed with Neanderthals in their ancestry. So a model that might explain the data is   that you have sparks coming out of a kind of  forest fire of humans expanding in the Middle   East or Near East. ..."

"very difficult to understand what's going on. The big picture is interesting in two ways. First,   you're not thinking crudely in terms of the  major species or the major subgroups of humanity,   like..."

"the agent of the black death, but actually without  the plasmid that contributes to bubonic plague.   That's required for flea-rat transmission.  So it must have been pneumonic plague with   an aeroso..."

"of that? One thing is that it seems to be coming  from steppe rodents, probably. Maybe the people   on the steppe—I mean, they are still dying  of it—are somewhat more protected from it.   Then it spr..."

"They are not as focused on farming, although  some of them are, as the people who came before.  This is so crazy. Just for the audience if  you're keeping tally, we have this one bacteria,   Yersinia ..."

"I don't know what the percentage of deaths was. It's estimated to be not the primary pathogen,   but who knows? In any case, there's others  too. Some of the other plagues in the Roman   empire are de..."

"shift in terms of how it adapts. You might  actually see that in terms of adaptation on   the genome. You might expect to see a quickening  of natural selection or a change. I don't think   we know th..."

"different. There are not genetic changes  that differ dramatically across populations.  There's a kind of disconnect. It's tempting to  think evolution has stopped from one perspective,   because ther..."

"The immune thing makes sense. There  are obviously more diseases. In what   direction is the metabolic thing pointing? One example of this is that there's very   clear downward selection against body ..."

"we have any sense of what it looked like when  different populations came into contact with each   other. In many of these cases, you're talking  about 90-95% of the population being replaced,   to th..."

"The Nazis used this idea to argue that these were  spreads of Aryans moving across the landscape,   being very disruptive and violent. The  reaction after the Second World War was to say,   “We don't ..."

"been something of a reconciliation after the book.  Archaeology is trying to reconcile itself with the   DNA data. It's arguing about the subtlety of  these interaction events. People talk about   wha..."

"a period of well less than a century. Do we know whether they were organized?   In more modern versions of this, when Cortés  goes to the New World, he's serving fealty to   the emperor of Spain. Or y..."

"So we really don't know what was going on. We really don't know what was going on,   but imagine if you were part of a community where  there's a certain culture. We’re getting this from   reconstruct..."

"They're the world's first extreme mobile  pastoralists, but they can't get further   than the steppe. They expand into Europe. They  expand into the little island of the steppe that's   in the Great H..."

"Yamnaya expansion is very male-biased. It expands  to the edge of the range. They encounter the   Corded Ware complex people. Then what happens  is the Corded Ware complex people interact   with the Y..."

"It's completely empty of people until 3,000 years  ago. Suddenly, these people from Taiwan go through   the Philippines. They skirt the edge of New Guinea  and the Bismarck Archipelago. They get to Va..."

"actually see evidence of males and females  behaving differently, it proves that there's   socially asymmetric behavior of two groups  as they interact. What it means is confusing.   It could be femal..."

"I don't know. It may be a numerical issue. If  you look at the part of the world where we have   the best data in the Holocene, the last 10,000  years, there are places of long-term survival   of hunt..."

"Maybe the right way to think about this is  that you have a population in the Near East,   for example, that is just encountering waves and  waves of modern humans mixing. There's so many   of them th..."

"I don't know. It's very speculative. I'm very  tempted to think that there's so many of these   groups that some of them would eventually  have gone down this route. One example of   this that's inter..."

"Maybe that's true. But the other way people  often say it is that we're in these cyclical   periods of a few tens of thousands of years.  The Holocene, the last 12,000 years or so,   is a period of wa..."

"is and so on. What they're referring to is if  you roll back 20 or 30 generations, where your   ancestors are scattered in proportions. But then  if you roll back 3000 generations, there's some   in E..."

"one point, there's never a singularity. I don't know if you're familiar with Nat   Friedman's Vesuvius Challenge. I don't know  if you saw that when it was going around. It’s   the scrolls in the libr..."

"maybe somebody will come up with a  cool new technique to figure it out.  There's many things in this area. I probably  should give you a single answer. The basic   answer is that we need DNA from Afr..."

"there's been nothing, we find Denisovans. We find  people we completely didn't expect to see before,   that breaks our understanding of the past. The other area where I am super excited,   and a thing..."

"the neurons to reassemble a photograph. It was  a perfect reassembly of the photograph. They   had actually completely learned how this  macaque's brain represents the photograph   going through the b..."

"Gokhman and Liran Carmel, with the voice box where  everything pushes in the same direction and goes   up to 100% and shifts all in the same direction  in an incredibly simple and simplistic way.  If ..."

"We're engaging with this in some way right now  because we have incredible data from Europe in   the last 10,000 years with huge numbers of  samples. We can watch very small changes in   frequency ove..."

"that's really qualitatively profound. Interesting. All right, I guess we need to   find the million dollars first. But somebody, if  you've got a million dollars, and somebody else,   if you got the i..."

"What happened in India is that it froze.  The mixing started, and then it froze. The   freezing happened 2000 to 3000 years ago. It  froze because of cultural change. What happens   in India is you ha..."

"traditional communities. The three steps are the  coming together of very different populations,   then convulsive and profound mixing of groups  that had previously not mixed, and then locking   into..."

"like what it's like in Silicon Valley right now.  You’re constantly doing new things and bringing   some skills to bear that are useful. You’re  hopefully trying to be respectful of the people   one w..."

"to know about the time periods before writing,  when at some point one didn't even imagine one   could learn anything. They’re excited  about this new type of information.  Sometimes people are dug in..."

"did come from the steppe. It's kind of  amazing it did. Maybe it's from disease,   maybe it's from something else. Who knows what it  is? That's a very interesting topic. But we adapt,   we learn. So ..."

"That's a great place to close. David, thank you  so much for coming on the podcast. I highly,   highly recommend your book, Who We Are and  How We Got Here. It’s just so wild. Basically,   a lot of th..."