Video: Homo sapiens Meets Neanderthals: The End of a World
Hallam L. Movius, Jr. Lecture Series
Lecture by Jean-Jacques Hublin, Professor at the Collège de France (Paris), Emeritus Professor at the Max Planck Society
The arrival of Homo sapiens in the mid-latitudes of Eurasia 48,000 to 45,000 years ago and the disappearance of the Neanderthals some millennia later mark one of the most pivotal episodes in human evolution. Drawing on cutting-edge work in archaeology, paleogenetics, and palaeoproteomics, Jean-Jacques Hublin’s lecture illustrates how this process was neither sudden nor uniform. In Western Europe, early modern humans entered the Neanderthal world far earlier than once believed, at times encountering and interbreeding with local populations. Instead of a simple geographic expansion, the evidence points to a complex mosaic of migrations, contacts, and extinctions. This led to a gradual reconfiguration of human populations from a world shared by multiple human forms to one inhabited by a single surviving lineage.
Presented by the Peabody Museum of Archaeology & Ethnology and the Harvard Museums of Science & Culture.
Recorded March 25, 2026
About the Speaker
Jean-Jacques Hublin has held the Chair of Paleoanthropology at the Collège de France since 2021, after serving as a Visiting Professor at the institution from 2014. He currently leads the Paleoanthropology team within the Interdisciplinary Center for Research in Biology (CIRB).
After beginning his career as a researcher at the French National Centre for Scientific Research (CNRS) ) from 1981 to 1998, he joined higher education as Professor at the University of Bordeaux where he taught from 1999 to 2004. In 2004, Professor Hublin founded the Department of Human Evolution at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, which he directed until 2021. Under his leadership, the department became one of the world’s leading centers for research on human evolution.
Professor Hublin has held visiting or teaching appointments at major international institutions, including the University of California, Berkeley, Stanford University, and Leiden University. He is the founder of the European Society for the Study of Human Evolution (ESHE) and served as its President from 2011 to 2020.
Jean-Jacques Hublin has played a pioneering role in the development of virtual paleoanthropology, particularly through the application of advanced imaging and computational methods to the study of fossil remains. His research has focused primarily on the evolution of Neanderthals and on the emergence, dispersal, and expansion of Homo sapiens across Eurasia and beyond. He has also made major contributions to the study of brain evolution, as well as growth and developmental processes in hominins. In addition to his empirical research, he has published influential work on the history and intellectual foundations of paleoanthropology as a scientific discipline.
To address these questions, Professor Hublin has conducted extensive fieldwork in Europe and North Africa and has authored more than 460 peer-reviewed scientific publications. His work has significantly reshaped current understanding of the biological, cultural, and historical processes that underlie the emergence of modern humanity.
He is a Knight of the French National Order of the Legion of Honour and has been awarded the Wissam Al-Kafaa Al-Fikria, Morocco’s Order of Intellectual Merit, by His Majesty King Mohammed VI. Among other distinctions, he received the International Fyssen Prize in 2021 and the Balzan Prize in 2023, the year he was elected to the French Academy of Sciences.
Transcript
Homo sapiens Meets Neanderthals: The End of a World
[00:00:08.00] Welcome. It's great to see so many people here this evening. My name is Jane Pickering, and I'm the-- I have to remind myself who I am. I'm the William and Muriel Seabury Howells Director of the Peabody Museum. And I'm delighted to welcome you guys all here in the lecture theater and then our online Zoom audience.
[00:00:31.72] And this is a very special evening. It's this year's Hallam L. Movius Jr. Lecture, presented by the museum, the Peabody Museum, but also a partner of the Harvard Museums of Science and Culture, together with the Department of Human Evolutionary biology, the Department of Anthropology, and the American School of Prehistoric Research. So there's lots of us behind this.
[00:00:56.88] And I want, on behalf of all those organizations, to offer my heartfelt thanks to the Movius family for their generous support of this lecture, which makes it possible and for us to all be here tonight. And I know some members of the family are online, so I just want to look directly, I hope, at the camera and say, thank you very much. We deeply appreciate it.
[00:01:20.25] And we are also very honored to welcome tonight a distinguished speaker, Professor Jean-Jacques Hublin. I think I said that right. It's a long time since I did French.
[00:01:33.45] Drawing on cutting-edge research in archeology, paleogenetics and paleo proteomics, Professor Hublin will examine the disappearance of Neanderthals and the rise of Homo sapiens in Eurasia, tracing the complex processes that gradually transformed a world shared by multiple human forms into one inhabited by a single surviving lineage. After the lecture, I do invite you to join us in the galleries of the Peabody Museum to enjoy some wine, some cheese, some conversation. It's up on the third floor gallery, and there will be people in that direction to direct you up. So I hope that those of us in person are able to join us upstairs after the talk for it.
[00:02:21.78] To learn more about additional upcoming programs-- we've got quite a few events still upcoming this semester-- I invite you to visit our website, peabody.harvard.edu, and you can also sign up for our e-news there as well. So it is now my pleasure to introduce my colleague Dan Lieberman, who is the Edwin M. Lerner Professor of Biological Sciences and Professor of Human Evolutionary Biology, and he will introduce our speaker. Thank you.
[00:02:51.60] [APPLAUSE]
[00:02:55.02] Thank you, Jane. It's a real pleasure to be here. Before I introduce Professor Hublin, let me just again thank the Movius family. For those of you who don't know, Hallam Movius, who after whom this lecture series is named, was, well, a preeminent Paleolithic archeologist. He was a graduate of Harvard College back in the day, I think, I think 1930 or something like that, a long time ago. Then he did his PhD here at Harvard.
[00:03:24.59] Then he served in the war all over the place. He was in the Air Force and, I believe, traveled all over the world for the US government and then came back to Harvard as a Paleolithic professor of Paleolithic archeology here and had an enormous, just incredibly important effect on Paleolithic archeology, both in the United States and worldwide.
[00:03:47.79] He's most famous for two things. One is something called the Movius line. Some of you may have learned about this in college, but because he had traveled all over the world and had looked at archeological collections everywhere, he appreciated that you could draw a line across part of Europe and at the edge of Europe and Asia and that, on one hand side of the line, there were lots of handaxe cultures And, On the other side of the line, there were basically no handaxes.
[00:04:14.02] And although there's people keep finding occasional handaxe here or there in Asia, it's still basically-- his insight is still basically true. And we still don't really quite understand why there are so few handaxes in Asia.
[00:04:25.78] But the other reason he became extremely important was a series of excavations, the most important were at a site called the Abri Pataud in the town of Les Eyzies in France. If any of you have not been there, you should go. It is one of the most charming, beautiful places on the planet.
[00:04:42.38] And the Abri Pataud had a series of layers that go from almost 50,000 years, up to about 17,000 years, traversing three different Upper Paleolithic cultures. And it was a landmark excavation bringing together all kinds of different disciplines, trained a lot of very famous archeologists. And if you go to the town of Les Eyzies-- which I, again, cannot recommend too highly.
[00:05:08.35] It's in the Dordogne. The food there is exceptional. It's charming. It's beautiful. It's really God's country in many ways if you like paté, armagnac, et cetera.
[00:05:17.61] [LAUGHTER]
[00:05:17.77] But I don't want to go on too much. But in the town of Les Eyzies, there's a hotel called the Hotel Cro-Magnon. And in the Hotel Cro-Magnon, in the hallway, there are lots of photos of the excavation of the Abri Pataud. And you can see pictures from the old days and have a delicious dinner.
[00:05:34.61] We can also go to the site of Abri Pataud, where there's a museum now, and see the results of the excavation. So again, thank you to the Movius family for giving this opportunity every year to invite one of the best-- to invite our Paleolithic archeologists to come speak at Harvard.
[00:05:55.13] And this year, we have really a superstar, Jean-Jacques Hublin, who I've had the privilege of knowing for 30 years now-- we've been friends for 30 years. Actually, 29 years.
[00:06:05.77] [LAUGHTER]
[00:06:06.39] But I can know that because my daughter was in utero when we first started working together. But Professor Hublin has had a really remarkable career. He did his undergraduate degree at the Université de Paris at Pierre and Marie Curie. He did his PhD at the University of Bordeaux, I believe, with Professor Bernard Vandermeersch, who I worked with when I was a graduate student.
[00:06:30.87] And I first got to know Jean-Jacques Hublin's work because I remember one of my advisors, David Pilbeam, pointed out to me that there was this really interesting guy in France who was doing unusual work. It was very un-French-- I remember that's what David Pilbeam said-- because at the time there was this idea that Neanderthals just basically were French. They must have been carrying baguettes. They just appeared in France.
[00:06:56.80] And Jean-Jacques really changed how we think about Neanderthals. He worked on how Neanderthals evolved and how they interacted with modern humans. And as you'll see from his talk, he's exceptional in the sense that he combines completely fluidly-- he's as much an archeologist as he is an anatomist and paleontologist as he is now a geneticist and combines all three of these fields completely, fluently and interchangeably at really deep and levels.
[00:07:32.20] After he was at the-- I met him in Paris when he was at the Musée du Luxem. He then moved to Bordeaux, and then he became the director of the Human evolution Group at the Max Planck Institute of Evolutionary Anthropology, where his impact is still being felt. And now he's a professor at the Collége de France in Paris, which, if you don't is a very, very, very distinguished position. These are the saints of the academic world of France.
[00:08:03.09] And so it's a real privilege to have him here. And I was lucky enough to have spent some time at the Collége this fall. So without further ado, let me introduce Professor Jean-Jacques Hublin for to talk about how humans and Neanderthals interacted.
[00:08:18.93] Thank you. Thank you.
[00:08:20.03] [APPLAUSE]
[00:08:23.73] Good evening, everyone, and thank you for coming to listen this lecture. Of course, I want to add my gratitude to all what has been said about the family of Hallam Movius Jr. I'm very grateful the family allowed me to come to a Cambridge, Massachusetts, and meet, again, with, as you understand, colleagues but also old friends like Dan and many others. I must say, I had a very busy day today, speaking, and chatting with very interesting people. And thank you, Dan, for your very nice words also.
[00:09:10.74] One thing that Hallam Movius Jr. taught us is that, in fact, if you look at the evolution of Paleolithic industries throughout the Old World, you have very different stories depending on what part of the world you are. And Dan Lieberman mentioned the story of the Movius line, which is still something that I think is to be considered when you look at poetic industries.
[00:09:41.70] And what we have learned since the time of the research by Movius is that, in fact, when you look at biology, there is also a huge diversity of hominins much larger than what we have thought could be possible in the past. So what you have here is a sort of simplified tree showing what kind of species of hominins existed during the last million years or so.
[00:10:15.67] And what you see is that there is only one of these bars here that represents our own Species Homo sapiens is the only bar that reached the top of the frame, which basically means that the only species of humans existing on Earth today. And well, by the way, I think that's a nice thing because, if we would be in a situation like we have been for hundreds of thousand years, we would have several kind of hominins peopling the Earth.
[00:10:52.16] And so something that looked to us very normal somehow, that there are the same humans all over the place, in fact, is not true if you move in a very shallow past, in fact. So just, say, more than 40,000 years ago, you had all these different hominins existing. And in particular, you have here a lineage that originated in Eurasia that gave two sister groups. Let's call them species information, the Neanderthals and a group that has been discovered in the not long time ago in 2010 that existed in Asia.
[00:11:39.96] And that is called the Denisovans. And this group is the sister group of Neanderthals. So in other words, we have a divide between an African world, where our species evolve, and an Euroasian, world where Denisovans and the Neanderthals evolve. And at some point, as you see, our species replaced all the others.
[00:12:06.13] And I think, from my point of view, this is really the most spectacular event in the hominin evolution of the last million years and arguably the most important event of the whole human evolution since there are hominins on Earth. And of course, we would like to know exactly how and why this happened, why our species replaced the others.
[00:12:34.37] And in fact, there are very few other places on Earth where you can really analyze what happened. We know what existed before. We know what existed after. But in most places, we don't know exactly what happened at the time of the replacement.
[00:12:52.04] And in Europe because Europe is a place where people have been doing archeology for a century and half, we have a lot of sites, a lot of hominins, also fossil hominins. And to some extent, we can document this process. So one thing I want to emphasize is that if we look at this divergence between Neanderthals and the origin of our species, what's really striking is the kind of difference in terms of phenotype, in terms of anatomy that we see between these two recently separated branches of hominins.
[00:13:42.47] Just to give you an idea of that, here on the right, you have two skulls of two sister groups of apes, chimpanzees, actually. So these two species of chimpanzees, bonobos and common chimpanzees, got separated something like a million and half years ago. And I don't know in the audience if there is anybody able to see the difference between the two skulls, but you really have to be a very good anatomist to see some kind of difference.
[00:14:14.97] But the difference between Neanderthals and Homo sapiens, that diverge much more recently, less than a million year ago, maybe 800,000 years ago, something like that, well, if my granddaughters who are seven years old would be here, they could perfectly explain to you what the difference in anatomy between the face of these two guys. So it's quite spectacular.
[00:14:41.01] And if you go into the internal anatomy of these skulls, you would find incredible differences. For example, the middle here, ossicles of a Neanderthal and a human are as different as what you would observe between a human and a chimpanzee or a gorilla. So it's a major difference in terms of phenotype.
[00:15:06.81] Just to refresh you, this is the world of the Neanderthals. So this blue area is a place where you find Neanderthal remains. Actually, most of the sites where we have Neanderthals are concentrated in the West part of this geographical distribution.
[00:15:29.65] And here in the Far East, Southern Siberia, Altai, they went there, but they went there, I would say occasionally. And they went there occasionally, especially during interglacial events, period that were less cold than others, because, during these time periods, the Caspian Sea has a lesser extension than it is today. And so you can have this expansion of hominins in the mid-latitudes quite far east, but during glacial events, the Caspian Sea is much more extended north, northward. And so you have a sort of geographical barrier in this area.
[00:16:18.10] So the question is, what kind of interaction we see between the African world of the sapiens, where they evolved, and the Neanderthals tools? And of course, one of the main question is, when exactly the origin, the ancestor of modern humans moved out of Africa and enter into this domain? And what we have learned from archeology, from paleontology, and also from paleogenetics is that probably there were several occurrence of these contacts between Neanderthals and African world.
[00:17:06.63] And to start with, we know from ancient DNA that there were already contacts a long time ago, probably more than 250,000 or 300,000 years ago. And we know that because we have in the genome of the late Neanderthals signs of what we call an integration of a part of the genome of the African people or ancestors of present day humans.
[00:17:41.56] This integration is an integration of what we call mitochondria DNA. This mitochondria DNA is something that is transmitted through maternal lineages. And so it explains that, when you built up a tree, looking at the phylogeny of all these groups, there is a discrepancy between a tree that is built on all the genome and a tree that would be built only on this mitochondrial DNA. And the same thing has been found for the Y chromosome and actually also for a little part of the rest of the genome.
[00:18:32.33] So this situation of integration of Y chromosome or mitochondrial DNA, it's something that we know in other species of mammals. And I just give you one example, which is the example of polar bears and brown bears. And it's pretty much the same situation, that you can build a tree from the genome of this species, different populations, and the tree that you build from the whole genome is different from the tree that you build from the mitochondrial DNA. And so it's something that is quite trivial.
[00:19:13.05] From the point of view of paleontology, we also know that occasionally we have in the near east fossil evidence of the presence of population of African origin. This is a maxilla, upper jaw bone, of a human that has been found in a site called Misliya in Israel near Haifa, and this maxilla is about 180,000 years old.
[00:19:48.94] In morphology, it's very different from what you find in Neanderthals, and it's clearly a Neanderthal hominin. And so back and forth in this part of the world, we have sometimes the occurrence of modern humans and sometimes of Neanderthals, and especially Israel is a place where this phenomenon has been observed.
[00:20:17.50] And people have been trying to figure out if there is a clear pattern in terms of timing and in terms of also association with archeology of these two groups. For a long time, it has been believed that Neanderthals were associated with a certain type of lithic industries that we call the Late Levantine Mousterian and early sapiens, early modern humans, with something that we call the interglacial Levantine Mousterian.
[00:20:56.51] But as a matter of fact, these two types of lithic assemblages are pretty much the same, actually. And the difference are mostly the kind of points like this, that we call Levallois points, that are a little bit more elongated in the sites where Neanderthals were living and a little bit shorter in sites where these subjects lived with the timing that is supposed to be older for the sapiens, let's say around 100,000, and something a bit younger for the Neanderthal.
[00:21:39.88] But frankly speaking, I think the main problem we have with this divide is that in fact, these two materials are so similar and so different from other Middle Paleolithic industries that you find elsewhere in Eurasia that is difficult to conceive that this population did not have some kind of interaction because actually they share the same technology. And some people have argued that maybe this is a hybrid zone where these two groups would connect through time for a long period. And I must say recently there have been the description of a mandible in a site called Nasher Ramla in Israel.
[00:22:35.57] And this mandible is associated to this kind of interglacial Levantine Mousterian with the shorter Levallois points. But the fact is that that's the wrong mandible that is found with this Mousterian because, if you look at especially the dental morphology, this mandible, to my opinion, looks pretty much like a Neanderthal mandible. And so again, the picture we have is that, in fact, in this part of the world, you have these two groups that share the same technology in fact, and the divide that has been envisioned, I think, is not valid.
[00:23:26.94] So we have exchanges between the two groups at the gate of Africa. We have this integration of mitochondrial DNA, Y chromosome that existed in the past. And of course, more recently, you had a final exit out of Africa, and we had this introgression of Neanderthal DNA into the genome of present day humans out of Africa.
[00:24:03.34] So most people in this room have about 2% of DNA of Neanderthal origin. What you have on this picture is a representation of the different chromosomes 1 to 22. Here is the X chromosome. It's a sexual chromosome. The inner circle represents chromosomes of present day humans, with the part of the genome where you can sometimes found Neanderthal DNA. And the outer circle represents the same thing for the Denisovans, the sister group of the Neanderthals.
[00:24:47.79] So just to be clear, all these little red bars on our chromosome is places where you can find Neanderthal DNA. But no one has all this Neanderthal DNA. So again, it's only 2% of the whole genome that is Neanderthal in the genome of present day non-African people.
[00:25:13.67] And of course, what's kind of striking is also parts of the genome where you never have Neanderthal DNA, which tells us that, for some reasons, natural selection has cleaned off our genome from this Neanderthal contribution in many parts of the genome. Actually, about 60% of the Neanderthal genome is never represented in present day humans.
[00:25:45.21] And places where you can't find Neanderthal DNA is places where this Neanderthal DNA is somehow useful, and it has been positively selected, in particular in relation with local conditions. The presence of certain pathogens and, for example, the immune system is a part of the genome where you find sometimes this integration. It's also likely that part of the introgressed genome of Neanderthals into the genome of present day non-Africans is just related to the fact that it does not hurt to have this part of the genome. So it's kind of neutral, and it can stay there without being very harmful.
[00:26:41.58] So the question is, how this happened, how this replacement of one population by another occurred in Western Eurasia? This is a picture taken from a old-- I mean, not that old-- paper by two geneticists from Bern University, Currat and Excoffier. And what you see on this slide is how they imagine the model, the expansion of sapiens into Eurasia.
[00:27:19.49] So it's a sort of wave. It's a one wave model with a front where you have this gradual incorporation of the local Neanderthals into invading migrants coming from the Near East. And the numbers that you have is numbers of generations during which this took place.
[00:27:50.59] So this model was kind of compatible with the archeological evidence in Europe. Why? Because there is a sharp contrast between the stone tools that you find associated to Neanderthals and what you find with this incoming Homo sapiens.
[00:28:12.36] This is the kind of assemblages that you have what we call the Middle Paleolithic in Europe, so very few standardized objects like this handaxe but a lot of flakes and points, which are kind of shapeless, in fact. It looks like people have been producing these flakes because they needed a cutting edge to do something, and then this object were probably dispatched.
[00:28:44.04] And this is in very sharp contrast with what you find after, say, 40,000 years ago in Western Europe, where we have something we call the Upper Paleolithic. And this Upper Paleolithic is very different. First of all, as you see, you have smaller artifacts. And these artifacts in general are very standardized.
[00:29:13.69] So these people have been producing a lot of blades and bladelets and especially to produce points. And these points were used to put at the tip of all sorts of projectiles for hunting. And so this seems to be a very, I would say, important production for these groups. By the way, I would say this prevalence of points and projectile is something that we see already in Africa before the spread of this hominins into Western Eurasia.
[00:29:56.45] So things were kind of simple. We had these Neanderthals producing this Middle Paleolithic with some handaxes and kind of shapeless flakes and things. And then you have this nice modern humans coming into Europe, moving as a wave, replacing them and with this very nice missile weapons to hunt and maybe sometimes to hunt Neanderthals.
[00:30:28.14] So, in fact, the problem with this model is that I insisted on this contrast between the Middle and the Upper Paleolithic. But unfortunately, reality is more complex than what we hope in general. And we have something between this Middle Paleolithic and the beginning of the Upper Paleolithic.
[00:30:56.78] And to start with, there is a kind of lithic assemblage that we call the Chatelperronian. As you see, it's something which is dated more or less between 44,000 and 40,000 years before present. And this Chatelperronian, in fact, looks pretty much like an Upper Paleolithic.
[00:31:20.25] You have these bladelets. You have these points, bone points. You have even a body ornaments. That's something that's unknown in the Neanderthal world. And the problem we have with this Chatelperronian is that, in two sites, there were Neanderthal remains that were found associated to this Chatelperronian, and so that's really something that contradicted this picture.
[00:31:44.23] And this is how archeologists and paleoanthropologists created this notion of transitional assemblages. So the idea was that, between the Middle Paleolithic and the real start of the Upper Paleolithic, there was this mosaic of lithic assemblages in Europe represented by these black lines. So the Chatelperronian is here in France and Northern Spain.
[00:32:17.06] But you see have others of these assemblages. There is one here in Italy that we call the Uluzzian. There is one in Northern, Northwestern Europe that we call LRG. There is one here called Boldnesian. And so the general wisdom with all these things is that it was something that was sort of intermediate between the Middle and the Upper Paleolithic.
[00:32:48.24] But because we had this notion that there was this replacement process, the way people interpreted these transitional assemblages was by imagining that the late Neanderthals have invented their own Upper Paleolithic, somehow, just before the arrival or at the time of the arrival of the modern migrants into Europe. Of course, this was kind of, I would say, surprising coincidence, but this is the way that these transitional assemblages were interpreted.
[00:33:29.21] And what I want to show you now is that, in fact, this scenario of the one-way peopling coming onto a world where Neanderthals are themselves evolving to create their own Upper Paleolithic has been completely falsified by the work in the last, say, 5 or 10 years. And now we have a scenario that is quite different.
[00:33:57.37] It started already in 2011, when one of my colleagues, Stefano Benazzi in Italy, described two teeth. So it's not much. It's just two teeth coming from one Uluzzian site in the South of Italy.
[00:34:20.90] And these two teeth were modern teeth. There are teeth, middle teeth, from children that had a modern morphology. And of course, this did not fit at all this picture of the Neanderthal making their transition to some kind of Upper Paleolithic.
[00:34:44.58] The problem we had with all these transitional assemblages is that, besides the Chatelperronian, where we had these two or three occurrences of Neanderthal remains, for the rest of the transitional assemblages, in fact, we had no much human remains to decide who made what. So we only knew that these things were at a very short length in terms of duration on the land and they existed in different parts of Europe. And, in fact, with this paper of 2011, basically falsifying the notion that the Uluzzian was made by Neanderthals, there was a series of new discoveries that basically have shown that most of these transitional assemblages, in fact, were made by modern humans.
[00:35:40.08] So how this happened? It happened mostly because people start introducing new techniques to analyze the archeological assemblages of these sites. The dream of all the paleoanthropologists is to find fossils a nice skull, a nice skeleton that would end in a museum and make you famous, could give it a nice nickname.
[00:36:09.69] But to tell the truth, since I was a graduate student in France, only one of these fossil has been found. So I realized that, if I wanted to wait until another one was found, I may never have the answer to the many questions about the transitional assemblages. And so me and others moved to other techniques and in particular a technique called ZooMS, which means Zooarchaeology by Mass Spectrometry.
[00:36:49.05] And it is about studying this kind of mass of small bone fragments coming from archeological sites. So in archeological sites, you find stone tools. Sometimes you find from time to time a nice bone that you can identify as belonging to a reindeer or a viceroy bear or something like that.
[00:37:13.30] But the vast majority in terms of volume of what goes outside of a Paleolithic archeological site, it's something looking like that. And thanks to the work of a group of scientists at the University of York in the UK, we found a technique to use a tiny piece of this bone fragments to extract from this tiny piece a bit of collagen still preserved in the bone.
[00:37:51.18] And then these fragments of collagen can be broken using enzymes like trypsin or others. And then these fragments of proteins that we call peptides, they are passed into a mass spectrometer that basically measures the size of these fragments. So if you imagine, a protein is made by a series of amino acids and that this series of amino acid can be seen like an alphabet, you have cisors that are going to cut this alphabet each time you have a certain sequence.
[00:38:38.59] And so the collagen is a very conservative protein. So pretty much the collagen of any mammal looks the same. But there are little differences from one species to another. And so imagine you have the text of a novel where you are going to cut the band of paper each time you have one given word or one given sentence.
[00:39:06.48] And so if it's always the same novel, you're going to always have the same piece of papers. But if you have different novels, you're going to have different pieces of papers in term of size. It's exactly what we try to measure with this mass spectrometer.
[00:39:23.84] And so when you do that, you get a spectrum like this, with peaks represented the quantity of these peptides. And along this axis, these peaks are arranged depending on the mass on the size of these peptides. And what you see is that for different species of mammals, here you have two species of rat. You find the same kind of spectra but with differences if it's not the same species.
[00:40:01.39] And so this is a very-- first of all, it's a very fast and very cheap method. And you can treat a lot of bone fragments. And if you do that in a site where you have a lot of these fragments, you can identify what all these fragments are in terms of species, what kind of mammals they belonged. This is used by zooarcheologists who want what kind of animals humans were exploiting.
[00:40:34.41] But if you do that on a very large series of bone fragments, say, over 1,000 or 2,000, from time to time, you are going to find one fragment that is a human. And this piece of human, of course, otherwise would be completely invisible because there is no any morphological feature allowing you to identify that. And then after you have identified this human among all these fragments, you can do direct dating by radiocarbon of this fragment. And you can also pass this fragment to your colleagues doing paleogenetics, and they can extract DNA.
[00:41:24.22] And you can extract a wealth of information from something that will never end in a museum, never will make you famous. You cannot give a nickname to the fragment. But it's incredibly beneficial to science.
[00:41:43.92] And I want to show you one or two examples where this kind of technique has been used to resolve this question of, who made the transitional assemblages? So I start with a site called Bacho Kiro. That's a site in Bulgaria. It's about 70 kilometers south of the Danube Valley.
[00:42:06.75] It's a site where several groups of archeologists have been working since the beginning of the 20th century. And we resume excavation in the site about 10 years ago. And the reason why we resume excavation in this site is because we have in this site one of these weird assemblages that are not really Middle Paleolithic, but they are not either Upper Paleolithic, something in the site that has been Bachokirian that is called sometime initial Upper Paleolithic. And it's basically represented by these large, thick blades that sometimes are truncated to produce other tools.
[00:42:58.20] And this is kind of typical of these industries that we cannot really classify as Neanderthal or sapiens med. Actually, this initial Upper Paleolithic is something that is known in not just in Eastern Europe, in Bulgaria, but also in the Near East. Here there is a couple of sites where this stuff has been found.
[00:43:25.84] And there have been a suspicion that these kind of assemblages, in fact, is a marker of the expansion of early Homo sapiens out of Africa into the Near East and from the Near East into Europe. And actually, we also find these kind of assemblages further East in Central Asia and as far as the Altai and even Mongolia.
[00:43:56.73] And so in Bacho Kiro, by sorting thousands of these bone fragments, we could extract several pieces of hominins. And these pieces of hominins, they were dated, as I said, and they were also given to specialists of paleogenetics to see what kind of DNA they have. And what has been first studied is this mitochondria DNA that is a tiny part of our genome, transmitted only along maternal lineages.
[00:44:34.05] And I mean, the first results that we got from this study is that for sure these hominins who made these so-called Bachokirian industry or initial Upper Paleolithic were not Neanderthals, but were early Homo sapiens. And more precisely, in terms of mitochondrial DNA, this bone fragment showed that we had several mitochondrial DNA haplotypes represented in the site, belonging especially to a group of variants of the mitochondrial DNA that we call haplotype M and N.
[00:45:26.91] And these haplotypes, they descend from an African haplotype called L3. And it's really this connection between M, N, and L3 has been used a lot to support the African origin basically of these early Homo sapiens out of Africa. And furthermore, the specimens from Bacho Kiro, they route very close to the-- I mean, they place themselves very close to the route of these lineages. And so it's fully consistent with the notion that they have a recent African origin.
[00:46:11.08] And what has been most surprising about these remains from Bacho Kiro is that, when we date them, what we found is that they are much older than what we thought. You remember I told you people had this idea that modern humans move into Europe around 40,000 years ago. And in this case, we had specimens that were dated more between, say, 43,000 and 45,000 years ago, so at least 5,000 years older than what we expected.
[00:46:50.53] And why does it matter? It matters because it's much older than the age of these late Neanderthals that I mentioned in the beginning of my talk. I told you, in Europe, we have the Chatelperronian associated with Neanderthals. And these Neanderthals, these late Neanderthals are more in the range of about 41,000, 42,000.
[00:47:19.33] So this meant that at least 4,000 years before the last Neanderthals got extinct in Europe, you already had early Homo sapiens Serbians in the North of the Balkans. And so, of course, this depicted a picture quite different from what we had before, not just in terms of timing, but also in terms of association of these hominins with this so-called transitional assemblage.
[00:47:56.06] And later, the group of my colleague Mateja Hajdinjak sequenced not just the mitochondrial DNA, but the whole genome. And here you have the chromosomes of one of the individuals from Bacho Kiro. And as I showed you in one of my first slides, you see these little blue bars representing pieces of Neanderthal DNA in the genome of these people.
[00:48:34.58] And the interesting thing, when you look at this contribution of the Neanderthal DNA in the chromosome of one individual from Bacho Kiro is that you see that you have pieces of Neanderthal DNA of very different size. And actually, the size of the segments of Neanderthal DNA that you find in the genome of non-African, the size tells you something about the number of generations that pass since the moment where this contact, this genetic contact, occurred.
[00:49:14.37] Why? Because, at each generation, because of the production of haploid gametes and the way reproduction works, the piece of Neanderthal DNA present in the genome tend to fragment more and more a long time. And what we see in this chromosome is that actually you have two classes in terms of size of these fragments of Neanderthal DNA.
[00:49:47.24] You have very small fragments that result from a contact between the ancestors of this individual and Neanderthals a long time ago, let's say, 80 generations or something like that or more. But you also have big chunks of Neanderthal DNA. And these big chunks means what? They mean that, in addition of genetic contact that occurred somewhere in the Near East at the gate of Africa, locally these guys, again, hybridized with local Neanderthal, just like five or six generations before the time this individual lived and died.
[00:50:33.89] And so you have two generations of contribution of Neanderthal DNA in this chromosome. And the other thing that the geneticist discovered is that, if you look at the genome of these individuals, actually it's almost a dead end. Somehow it looks like they have no or almost none descendants in Western Eurasian today. And I mentioned that these kind of assemblages is also found in Central Asia and even further East. It's there in far East of Asia that you find a little bit of this population remaining.
[00:51:21.61] But basically, the main message was that, locally, it's a group of modern Homo sapiens that move into Europe but died out finally, was replaced by other groups of Homo sapiens. At the time we published this paper on Bacho Kiro, there was another publication about another site called Zlaty Kun that is in the Czech Republic, so much further West.
[00:51:56.42] And in Zlaty Kun, a skull has been discovered back in the '60s. Nobody knew exactly how old this skull was. There was no way to direct date it because it has been consolidated with some kind of glue that contaminated the samples, et cetera. But it has been possible to extract a fairly complete genome from this individual.
[00:52:22.70] And using this genome, we can say that this individual also lived probably around 45,000 years ago. And when you look at the Neanderthal contribution in the genome of Zlaty Kun, the picture is quite different from what we have in Bacho Kiro. Well, first of all, here the Neanderthal contribution is presented in red, not in blue. I'm sorry for this confusion.
[00:53:00.07] Geneticists are still debating about whether Neanderthals are more on the Republican side--
[00:53:05.99] [LAUGHTER]
[00:53:09.61] --or Democrats. But OK, here is red. And the difference with Bacho Kiro is, when this genome was analyzed, what it showed is that this group is probably a bit older than Bacho Kiro. But although it's older, it did not locally hybridize with Neanderthals. So we have another population, another small population with a completely different history, a complete different destiny.
[00:53:41.08] And again, it's a kind of population for which we don't have descendants today. And last, I want to show you another of these transitional assemblages I mentioned, the LRG. So LRG is the short version of the Lincombian Ranisian Jerzmanowician, actually three different type of lithic assemblages that are found from the UK through Belgium, Germany, and Poland.
[00:54:18.20] And they are characterized by a certain type of points. In Germany, we also have this very spectacular large bifacial points. And so that's one of these assemblages that has been long considered as made by late Neanderthals that made their transition to some kind of Upper Paleolithic.
[00:54:43.30] And again, I mean, since the 19th century, after excavating and actually destroying a number of archeological sites, it has been impossible to find any piece of evidence about who made the LRG. And by working in a site which is actually the site on which the name of Ranisian has been created, it's a little town in Thuringia called Ranis.
[00:55:18.82] And in Ranis, there is a cave under this castle. And this cave has been already excavated in the '30s. And we resume excavation in the site. It's a bit complicated because, as you see, it's a very thick deposit. It's a cave of which the roof collapsed.
[00:55:42.43] So if you want to excavate, you have to go through this collapsed roof, big blocks, some big like my car. And so we had to make almost mining to go to the bottom of this excavation. And by using this technique that I mentioned, ZooMS, this extraction of collagen from pieces of bone, it has been possible in this new excavation to identify some human remains, again, not very spectacular, very broken.
[00:56:16.99] The collection that was preserved in a museum from the old excavation from the '30s has been also analyzed in a molecular way but also morphological way. And all in all, after doing all this, for an assemblage for which we never had any piece of human found for more than a century, we ended up having 12 specimens, which were hominins, where some of these pieces, some were from the same individual. But of course, that was another case where we had, in fact, early modern humans.
[00:57:01.92] So what I'm telling you is that one after the other, all these so-called transitional assemblages fell, and I would say they fell on the side of modern humans. And they were not Neanderthals anymore, again, the chromosomes of specimen from Ranis, here compared with the chromosome from the Zlaty Kun woman that I showed before.
[00:57:31.17] And the one thing that's really spectacular in Ranis is that, again, we have individuals who did not interbreed with local Neanderthals. And actually the Ranis population is very close from the Zlaty Kun woman. Actually, the Zlaty Kun woman is interpreted as a cousin at the fifth degree, but a cousin or a parent, from one individual from Ranis.
[00:58:07.25] I don't know if it speaks to you, but it blows my mind that you can connect individuals that live 45,000 years ago between two sides that are, say, more than 250 kilometers, one from the other, and find some kind of cousins from one side living in another. By the way, it says something about the territory that these groups were exploiting. And you see, we are still here with a situation where there is no integration of DNA coming from local Neanderthals. But this integration of Neanderthal DNA is the result of an hybridization that occurred like about 80 generations before.
[00:58:55.10] By the way, one thing I did not mention about Bacho Kiro, which is true also for Ranis and Zlaty Kun, is that this cleaning of the genome by natural selection, eliminating part of the Neanderthal contribution, is something that is very fast in terms of process, because all the deserts that I mentioned already, where you never have Neanderthal DNA, are already present in this population. Last but not least, I want to show you another kind of studies that we did in the site of Bacho Kiro and Ranis, and it's about climatic reconstruction.
[00:59:44.87] There have been for a long time this notion that the reason why this population moved from one place to another is related to environmental conditions. So in other words, that's probably true for the main out-of-Africa movements. We have good reason to think that it's climatically driven.
[01:00:09.79] But for Europe, a very popular idea was that, at a time when the climate was warmer, these guys living in the Near East and of African origin, we think, well, why don't we go there in Europe? Now it's warmer. And they would move into Europe.
[01:00:28.36] And so we have been investigating this climatic condition. Here is the picture of one of my former postdoc in Leipzig, Sarah Pederzani. And what Sarah has been doing, she has been looking at the variation in composition of one isotope of the oxygen. So oxygen-18 is a heavy form of oxygen, and the proportion of oxygen-18 varies with different things, the temperature, the distance to the ocean, and all sorts of things.
[01:01:07.32] And it fixed into the tissues because, especially in the past, people would drink the water where they live and consume animals and plants from their environments. And so if you look at a tooth of a horse or a large bovid, which is a tooth that has a continuous growth through time, you can sample all along this tooth and measure this rate of oxygen-18.
[01:01:41.61] And the curve that you see correspond to one winter, one summer. And again, you fall into a winter. So the growth of a tooth like that is about a year. And it's a continuous process. And we have models based on present day horses and bovids, et cetera, that allow us to convert these values of oxygen-18 into temperatures.
[01:02:09.05] And what has been found by Sarah Pederzani is that, in Ranis, if you compare the summer and winter temperatures extracted from this kind of tease to the modern reference, in other words, to the temperature that we have today in winter and summer in Thuringia, where the site is, what you see is that the winter temperature around this cave 47,000 years ago was about 18 degrees Celsius lower than it is today in winter.
[01:02:54.74] So I don't know if you ever passed a night of winter outside in Thuringia. It's not something you want to do. But if you imagine a temperature 18 degrees lower is basically the environment that you find in Northern Scandinavia, at the limit where trees can still grow, and so what we see with this-- and it's something that we saw also in Bacho Kiro-- is that these people, they did not move into Europe at a time where the environment was warmer and more comfortable, just on the opposite.
[01:03:32.39] Actually, what it looks is that they settled in Northwestern Europe earlier than further South. And so it looks like they settled, in fact, at the periphery of the Neanderthal world. You remember, you have Neanderthals living further South until like 40,000 years ago. And so it tells us that these guys, they had, I would say, the technical capability and the resilience to live successfully in this kind of extreme environment.
[01:04:12.49] So all in all, we have been able to reconstruct the relationship between all these populations. And what came out of these studies is recently two papers published in 2004, and addressing not just the relationship between all these groups, but also the question of the timing of the integration of Neanderthal DNA into the genome of these guys.
[01:04:48.93] And it's a picture that's quite different from the picture I showed you extracted from the paper by Kurat and Excoffier, with this wave of people moving into Europe. What you see is that you have small groups of people, a few hundred, probably, moving very far west into basically the vicinity of the Neanderthal territory.
[01:05:16.10] And there are like several, I would say, attempts that you could see that as failed attempts, somehow, because this population don't have much descendants today in Europe. And after several of these attempts, then only 40,000 years ago you had, I would say, the good wave, the one of the Aurignacian, the one I showed you with all these fancy points and standardized objects.
[01:05:50.66] So these two papers that were published recently, as I said, address the question of the timing of this Neanderthal integration into our genome, the genome of our ancestors. And if you would have asked geneticists five or six years ago when this happened, it would tell you something like maybe 60,000 years ago, maybe even more. But the big surprise with these two papers is that the age that was established for these 2% of DNA that we all carry out of Africa, it's much younger than what was expected somehow.
[01:06:40.23] You remember, there was movement back and forth in the Near East going back to 100,000 years ago, 180,000 years ago. But here we are talking about something that happened around 48,000 years ago. So it's quite young. It's very easy to understand how you can establish a date like that.
[01:07:01.57] You remember, I told you the size of this introgressed fragment tells you something about the number of generations that passed since it happened. So here you have the number of generations. And here at the bottom, you have the age of the specimens.
[01:07:19.60] And so you can have all this distribution. You create a regression of all these points. And this line is going to intersect the horizontal axis at a point where the number of generations elapsed is just zero, and it gives you the age of this integration.
[01:07:42.52] These two papers also have tackled several other issues about this integration. So now I'm talking about, I would say, the main integration, this two person. I'm not talking about what happened locally in Europe with some groups locally hybridizing or not. I'm talking about the main thing. And it looks like it's a one event that occurred between 49,000 and 45,000 years ago.
[01:08:17.13] And the other thing that I found really interesting in the conclusions of these papers is that, in fact, the conclusion of the analysis of this integration is that it comes from a single Neanderthal group or multiple groups closely related one to another. So in other words, it's falsified this notion that the integration of Neanderthal DNA that we have in our genome is the result of local admixture here and there in Eurasia.
[01:08:55.01] But more likely, it's something that's related to one event occurring somewhere at the gate of Africa. So in other words, the picture that we have today, this is, again, this Neanderthal distribution. We have a out-of-Africa movement, a last one that's kind of recent, probably around 50,000 years ago.
[01:09:20.34] These guys, they hybridize with a group of Neanderthals somewhere. We don't know exactly where but somewhere not very far from the gate of Africa because we find the same integration everywhere outside of Africa. So it's very unlikely that it happened, I don't know, somewhere in the Far East or in the Far West.
[01:09:45.54] And this source population, this sort of reservoirs have been given small groups producing these so-called transitional assemblages, these binary groups going West and East and being, I would say, not so successful in terms of descendants into present day populations. And finally, about 40,000 years ago, the same reservoir gave this, I would say, the good wave.
[01:10:20.25] So after the wavelets, we had the real wave, the Aurignacian wave. That's more recent. And this last wave is the one that basically probably led to the final extinction of the Neanderthals, especially in Western Europe.
[01:10:38.59] One of the conclusions of this scenario is that, when we say that there is still Neanderthal DNA in our genome and that Neanderthals living us, it depends what Neanderthal you are talking about. We're talking about Neanderthals living somewhere here. We are not talking about the Neanderthals that lived here like until 40,000 years ago because there it looks like it's probably an almost complete replacement that we have with no local contribution.
[01:11:15.20] I remind you, the only group that locally hybridize is the group of Bacho Kiro, and it looks like they don't have much descendants in present day Europeans. So in other words, yes, there is Neanderthal DNA in our genome, but locally here in places like Western Europe, local Neanderthal seems to have been completely replaced.
[01:11:39.44] So I think it's a big change of the picture we have of all these events. There are still some pending questions. So I tell you what I found really puzzling. First of all, what I find puzzling is the length of overlap between the first modern Homo sapiens moving into Europe and the last Neanderthals.
[01:12:07.77] Already in the Near East, in the place where this hybridization occurred, this initial hybridization, in one of these papers, the scenario that is envisioned is that, yes, it's a single event. But it's a single event that lasted 7,000 years. And for humans, 7,000 is quite long. And I remind you that, in Western Europe, we have early modern humans directly dated in Ranis in Germany at 47,000. And the last Neanderthals disappeared from Southern France probably around 40,000 or 41,000.
[01:12:55.56] So it's a huge overlap in terms of time. And personally, I have difficulties imagining how this is possible between populations that can interbreed. First of all, it shows that, if there was some kind of superiority of modern humans moving into Europe, this superiority was not overwhelming because it took a long time for to have a complete replacement.
[01:13:24.18] And I suspect that there was some kind also of barrier preventing the merging of this population because one of the very popular scenarios among archeologists is that local Neanderthals ended up being absorbed by incoming population. We saw that this did not happen. And so I think probably there is enough incompatibility in terms of reproduction between Neanderthals and sapiens to have a situation like what we have in other primates, where you can have different species of baboons, for example, in East Africa that coexist in the same region.
[01:14:12.96] These two species have been separated probably more than a million years ago. The radiation of baboons is in Africa. It's about in this kind of age. And they hybridize in a hybrid zone, so you can find a bit of the DNA of one species into the other.
[01:14:35.44] But all in all, they don't merge. They stay separate. And they stay separate because there is enough mechanism keeping them apart somehow. And it's very likely that something like that existed between Neanderthals and Homo sapiens.
[01:14:53.13] Other questions? So that's how the-- now I'm talking about the stones in my shoe. There is one site in Southeastern France called Abri Mandrin, where people have claimed to have found one tooth of early modern humans. That would be in a layer that's about 53,000 to 55,000 years old.
[01:15:22.05] We don't have DNA from this tooth. We don't have a direct dating of this tooth. Well, we'll see if they find another tooth and a better dating. Maybe this will confirm that this occurrence of early modern into Western Europe is even older than what we think.
[01:15:40.69] And we also have the problem of these Chatelperronian. You remember, I told you that the Chatelperronian looks pretty much like an Upper Paleolithic assemblage, and today it's the only transitional assemblage surviving as not being associated to modern humans. And so the question is whether or not it has been really made by Neanderthals.
[01:16:07.94] Recently there was the publication of this little thing that's a piece of pelvis of a baby that looks like a modern. But still, we have dozens of bone fragments and teeth clearly of Neanderthal natures in the time range of the Chatelperronian and sometime in Chatelperronian ranges. And of course, this raised the question of also interactions in terms of cultural interactions between the two groups.
[01:16:44.30] I show you the cover of two Nature paper, one I published in '96 and one in 2020. First of all, it shows you that if you wait long enough, you can propose two times the same cover to Nature.
[01:17:02.97] [LAUGHTER]
[01:17:03.63] But really, this shows the kind of body ornaments that we have in the Chatelperronian site in France associated to Neanderthals. This is the kind of body ornaments that we have in Bacho Kiro. And of course, the question is to what extent are these changes that we see possibly in the last Neanderthals has been triggered by the occurrence of modern humans. I thank you for your attention.
[01:17:35.09] [APPLAUSE]