DNA | Mammoths, Neanderthals, and Your Ancestors || Radcliffe Institute

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-Good morning, everybody. And welcome to the Radcliffe Institute for Advanced Study. I'm Liz Cohen. I'm dean of the institute. And I am delighted to welcome you to our annual science symposium, which will engage us all today in probing the past, the present, and the future of DNA. The Radcliffe Institute for Advanced Study is a distinctive intellectual community where scholars, scientists, and artists work at the forefront of their disciplines and across disciplinary boundaries. In fact, you might say that dedication to interdisciplinary work is deeply embedded in our DNA. And you can see its expressions in today's list of speakers, which includes a chemist, an anthropologist, an entrepreneur, and an explorer, as well as the prominent geneticist you might expect. I hope you'll take advantage of the opportunity to talk with our speakers by joining us for a reception at Fay House, right next door, immediately after the conclusion of today's symposium. There you will also find DNA related posters prepared especially for this conference, chiefly by students. These posters will be on display in the Sheerr Room of Fay House during the lunch hour, as well as during the reception. Radcliffe has a long and deeply embedded commitment to the sciences and to sharing advance scientific work with the public through conferences like this one. We are proud of our rich tradition of science programming, hearkening back to Mary Ingraham Bunting. She was a microbiologist, the fifth president of Radcliffe College, and the founder of the forerunner of today's fellowship program, which was called the Bunting Institute. We continue Mary Bunting's legacy through our yearly science symposium and through a related science lecture series. I hope you will come back for the lectures on DNA beginning on Tuesday November 3 at 5:00 PM when Dan Barouch, professor of medicine at Harvard Medical School and the director of the Center of Virology and Vaccine Research at Beth Israel Deaconess Medical Center discusses, and I quote his title here, prospects for a vaccine and a cure for HIV. For more information on this series and many other upcoming events, I hope you'll check out the calendar cards that we've put on your seats, as well as our website. Today's conference has been organized by our biological science faculty director, Janet Rich-Edwards. And I'm very grateful to Janet for her leadership. We're here today to consider the past, present, and future of DNA. And the very title of today's conference alerts us to how timely, but also in some ways how timeless, a topic DNA actually is. Swiss scientist Friedrich Miescher first isolated DNA in white blood cells in 1869. Its discovery revolutionized the science of genetics and also inspired an entire literary genre of microbiology as dramatic narrative. In 1926, The Microbe Hunters by Paul de Kruif ignited the imaginations of an entire generation of budding scientists. Half a century later, The Eighth Day of Creation by Horace Judson did the same for another generation. For decades, scores of biologists and geneticists have attributed their decisions to become scientists to reading The Microbe Hunters or The Eighth Day of Creation when they were young. In subject matter, both are books about microbiology. But in form, they are adventure stories. As one reviewer put it, they feature, and I quote, epics of science that come to triumphant fruition. The Eighth Day of Creation, for example, portrays James Watson and Francis Crick discovery of DNA's double helix structure in 1953 as the culminating event in molecular biology. It's a suspenseful thriller, and discovering the double helix is the climactic moment. The book was published 35 years ago in 1979. And yet, since then DNA research has continued to advance and has helped us to see life on Earth holy anew. It has challenged what we thought we knew about neanderthals, cancer, crime fighting, human personality, and more. Its discovery has changed medicine and spawned whole new industries. Even in my own field of history, which would seem to be as far removed from cutting edge molecular biological research as you can possibly get, it is being fundamentally altered by DNA. For example, advances in genomic archaeology have provided us with better understanding of why famines affected populations differently. Some human remains contain genes that show unusually high prevalence of lactase, an enzyme that breaks down lactose, the sugar that occurs in dairy products. The more lactase a person's body can produce, the more a person can tolerate and derived nutritional value from milk and butter. Populations with high levels depended less exclusively on grain for subsistence. And therefore could better withstand poor harvests in the short term. Because they were already accustom to supplementing low grain yields with milk. On the other hand, those same populations were much more vulnerable when epidemic diseases struck cattle. Very close to home, my own colleague in the Harvard history department, Mike McCormick, is reevaluating the Anglo-Saxon invasion of Britain on the basis of DNA research. Mike is not exaggerating when he calls human genetics, and I quote him, an extraordinary window on a vanished world of migrations and matings that take you back literally to the dawn of human time, end quote. The study of DNA then is more relevant to the study of history than might at first be obvious. At the same time, how scientists study, understand, and apply genetics also changes over time. So while DNA changes history, it also has a history. And we are living today in a watershed moment of that history. Let's look quickly at a case of DNA research now evolving. The emerging field of epigenetics studies how environment can alter the molecular processes that affect how genes get expressed. Researchers have shown that toxins, chemicals, and some kinds of trauma can alter how chromosomal code actually gets suppressed or articulated. Recent studies raise the intriguing possibility that social interactions might do that as well. For instance, research indicates that some genetic diseases progress differently in socially isolated people than they do in people with robust support networks. Learning more about how DNA replicates and expresses itself therefore might not necessarily reduce us to dehumanized chains of polypeptides, as some ethicists worried when the double helix was first discovered. It might instead help us to better understand exactly how and why the people in our lives, our friends and our families, have a transformational impact on us. The study of DNA in short began raising profound questions as soon as Miescher began isolating white blood cells in 1869. It continues to do so today. And it will persist doing that into the future. It is thus a most fitting topic for consideration here at the Radcliffe Institute, where we embrace open ended, complicated, and cross disciplinary investigations. To get us started, I would now like to hand things over to Janet Rich-Edwards. Janet is a Radcliffe alum and an epidemiologist with research interests centering on maternal and child health. She holds dual appointments at the Harvard Medical School and the Harvard T.H Chan School of Public Health. And she also serves as director of developmental epidemiology at the Conners Center for Women's Health and Gender Biology at Brigham and Women's Hospital. Her research interests include the implications of pregnancy complications for future cardiovascular disease and the impact of childhood abuse on chronic disease outcomes. Janet? -Good morning. Thank you Dean Cohen. And thank you all for coming here today. And special thanks to our speakers. Last Sunday, as my husband and I were up on the roof watching the lunar eclipse, we recalled the thrill of Apollo 11 landing there and the moment when Neil Armstrong stepped out of that module onto the moon's surface. I was seven years old. We had just had sheer wonder that man was stepping on the moon. My husband, looking up at that blood moon, said, it's still pretty amazing to think about. And here's what I thought. Yeah, it is. But it ain't nothing compared to what you're going to hear about on Friday. I'm that excited about today's program. For as marvelous as it is to go to the moon, it's equally marvelous and perhaps even more pretentious for the planet's welfare to be able to go into the mitochondria. As you'll hear today, the science of DNA is not only telling us about our past. It's already improving human health and planetary ecology. And its potential for the future seems limitless. But this technology is new, very new. And like any sharp tool, can be used for good or ill. And so we need to develop it thoughtfully and with safeguards. And so in addition to the science today, we'll be discussing the ethical aspects of this new world. There we go. When I was a kid, DNA was pretty simple. You had your nucleotides, the base pairs, A, T, G, and C. And you knew that the DNA in the nuclei of your cells was transcribed into RNA, which left the nucleus as messenger RNA bearing the code to guide the translation and assemblage of proteins from the building blocks of amino acids. Your genes on your DNA are the sections of DNA that actually code for these proteins that make up your cell walls, your antibodies, your enzymes, your hormones, your muscles, basically you. As you probably know, there are long stretches of DNA between the genes, sections that don't actually code for proteins. We've learned that this so-called junk DNA contains instructions for gene regulation, like switches that turn things on and off invisibly. I would say, unlike a Volkswagen diesel exhaust system. The various combinations of the four nucleotides form-- the four nucleotides form 64 distinct codes, or codons, that match up with 20 different amino acids. These amino acids, sorry, form the proteins that form your body and shape your behavior. But think about it. Four nucleotides, 20 amino acids, there are hundreds of naturally occurring amino acids out there that are just left on the table. What if we could recruit some of those amino acids to make new proteins? What if we could make more effective medicines with them? What if we could make new fuels? If we had a larger vocabulary of nucleotides, could we deploy DNA to make new things? But the first question is, can we even add nucleotides to DNA and get it to work? And that's exactly what Floyd Romesberg's lab at the Scripps Research Institute has done. As you'll hear today, he succeeded in creating a synthetic DNA with two new nucleotides, x and y. With six letters in your alphabet, there's a possibility now of 216 codons that can now code up to 172 amino acids. And you can see that the potential for creating new proteins then explodes from here. It's as if the original four letters limited us to the vocabulary of Hop on Pop. With all due respect to Dr. Seuss who I love, with two more letters, we begin to be able to write words that get us to Harry Potter. And who knows, with more nucleotides, suddenly we can write Infinite Jest. And then there's your mitochondrial DNA. If this is a cell, here's your nuclear DNA right there in the red. These little bodies here are your mitochondria. They are your generating bodies in every cell. The mitochondria exist outside of the nucleus. And they have their own DNA, a primitive circular DNA that we probably inherited from bacteria long, long ago. When I was in school, we use to learn about mitochondria at the very end of the section. It was an afterthought. You inherit your nuclear DNA from both your parents. Half your code comes from the nucleus of your father's sperm and half from the nucleus of your mother's egg. When they merge, your nuclear DNA is formed. But the egg also carries mitochondria in a cytoplasm. If you're a woman and you have children, you'll pass the same mitochondria along to your children. In fact, the mitochondria in your cells, whether you're a woman or a man, are the same mitochondria in your mother's mother's mother's mother's mother's line, all the way on back. So while your nuclear DNA is inherited from all your ancestors, your mitochondrial DNA comes from your maternal lineage. This fact offers up both promise and peril. Mitochondria are rather prone to mutation. They lack some of the genetic repair mechanisms that we have in nuclear DNA. And over time, over millennia, the mutations allow us to track who our ancestors were by looking at these mutation patterns across populations. If you're a man or a woman, we can trace your maternal genetic lineage through your mitochondria. Now, men have a second option. We can also trace a man's father's father's father's father's line through his paternal lineage through his y chromosome. So I was curious about this. Back in 2009, I ordered a gene testing kit from the National Genographic Project, which we'll hear about from Spencer Wells today. You can see here that it's just a simple cheek swab. I was curious about my own lineage, but even more curious about my husband's lineage. Mark is African-American. He's a dead ringer for Barack Obama. He is. You couldn't believe how many people ask him if he is Barack Obama. Or even "are you Osama?" has happened. What do you say? Like many Americans, the records that would allow us to learn about his family heritage just don't exist. So we were very curious to look at his DNA and trace back to his African roots. So first we did my mitochondrial DNA. And here's what we found. Like all humans alive today, my maternal line can be traced back to Ethiopia 150,000 years ago. My maternal ancestors left Africa in the second wave of people who did through the Saudi peninsula, probably following better game after the Ice Age retreated. We came up through Central Asia. Then banged a left and into Europe, where we probably would have bumped into the Neanderthals. And John Hawks will be telling us more about that mixture in our lineage. And then I discovered, not to my great surprise, that most of my genes hail from Britain and Ireland. So then we ran Mark's DNA. Smart scientist and feminist that I am, given the choice between running his mitochondrial DNA or his y chromosome DNA, I said, oh run your y chromosome DNA. We were so excited to see where in Africa his family had come from. So when we got his results, there was something of a shock. Mark's paternal lineage is more Irish than my own. Now, I have to say we were both dismayed. Because confronting us in Mark's genes was a story we weren't sure we liked, was the evidence of history. We were looking at a legacy that spoke of slavery, of human ownership probably, of race and gender dominance. It gave us some pause. Of course, if we thought about it for half a second, Mark's paternal line was not the place to look for his African heritage. We should have checked his maternal line. So that's what we did next. Mark's mitochondrial DNA, of course, told a different story. His mitochondrial mutations lead us to West Africa, probably a Fulbe or Fulani tribe. If we reran those results today, what is it, six years later, we would probably get even greater specificity. Because the more people who join this project, the better that it is able to map human migration. But our experience finding out about our heritage was, I would say, not an unmixed blessing. And I think there are real ethical quandaries when the genetic story line contradicts our own personal or our group's or tribe's identity and our beliefs about our origins. But bringing up the question of who has the right to determine your group's heritage. There's also a therapeutic side to mitochondria as well. Mitochondria can be diseased. They get flaws in their own DNA, which can be devastating to health. We'll hear this afternoon from Alison Murdoch of Newcastle University about the brave new way to prevent mitochondrial disease that is passed from mother to child. I'll give you a brief outline. There are a few ways to do this. This is one of them. If a woman has defective mitochondria and she goes to have a child, there's a strong likelihood she'll pass it on. But once she and her partner conceive, it's possible now to extract their healthy nuclear DNA from the unhealthy egg. If another woman with healthy mitochondria donates an egg, it's possible to strip out the nuclear DNA from that one, and replace it with the prospective parent's nuclear DNA. This gives the patient couple a chance to have a healthy child. This has been done successfully in humans. But as you can imagine, the process of creating life from three parents effectively, instead of the usual two, has raised some ethical issues. Dr. Murdoch will tell us about the technique and about the new legislation that has made this legal in the UK. We are also joined today by Jacob Corn from UCal Berkeley. He will talk about the technique you may have heard of called CRISPR, which makes it possible to, if you will, copy edit the genome, specific genes or their transcription factors, those on off switches in the junk DNA. This genome editing has the potential not to just prevent as in the mitochondrial scenario you just saw, but actually to cure many diseases, such as cystic fibrosis or sickle cell anemia. This of course has enormous ethical implications. This April, scientists in China reported the first CRISPR manipulation of a non-viable human embryo. If you follow the news, you'll know that many scientists have urged a moratorium on applying CRISPR to human germ cells, that's egg cells and sperm cells, until the full implications can be discussed among scientific and government organizations. But genetic engineering is already being used to create transgenic animals, sometimes known as Chimera, , as for the mythical beast that was a part lion, part eagle, part goat. In this case, a human hormone gene is inserted into a sheep's genome. The resulting transgenic sheep, otherwise perfectly normal, then excretes the human hormone into its milk, where it can be harvested to create inexpensive medicines and potential vaccines. ZMapp, the experimental Ebola drug, is a product of one of these transgenic molecular pharmacy experiments. But it's not just medicines. You may have heard of the spider goat, a regular goat who has received some DNA from the golden orb spider. This cartoon from Modern Farmer Magazine-- believe it or not, wow it's really modern-- is facetious. This goat does not actually fling webs. But it does secrete proteins into its milk that can be made into an elastic fiber that is 10 times stronger than steel. Imagine that, elastic and stronger than steel. This has the potential to be made into body armor, parachutes, surgical sutures, and other fantastic stuff. Other applications of DNA science will allow us to protect the planet. Many of you may have heard a recent NPR broadcast discussing the technique of sampling ocean water to measure the free floating DNA that is cast off, just shed, by fish, sharks, plants, whales, and other things as an inexpensive way of creating a real time ocean census. This would allow us to follow migrations of hard to track animals. Or take leeches, or more specifically the leech's lunch. They turn out to be quite useful. Because they suck the blood from just about anything. And they provide a good tool for censusing a forest. In the Yunnan province of Vietnam, rangers collect leeches off trees, note their locations with a GPS, bring them back to the lab, and put them in the blender. If you then use a process called metabarcoding, which amplifies sections of DNA, you can tell what species are in the forest. And using this, they've discovered that the shy and elusive saola, aka the Asian unicorn, which has not been seen in the wild since 1999, is not extinct. This information could be used to protect its habitat. But could we go further? Could we, for example, use DNA from one species, even an extinct species like the mammoth, to help another one? Beth Shapiro of UCal Santa Cruz will, for example, talk about how to clone a mammoth and perhaps how mammoth DNA might help to save modern day elephants by increasing their range. We will also explore with Greg Hampikian of the Innocence Project the use of DNA for better or worse to solve crimes. While the intention is to free the innocent and convict the guilty, there's also the potential of flawed science and bad forensic technique to convict the innocent. He'll be talking to us about that. And throughout the day, and with your help to bring up questions, and explicitly with the talk this afternoon of Art Caplan, the bioethicist from the New York University School of Medicine, we'll consider the ethics of this fast moving science. I think this promises to be a really exciting today. Thank you for joining us, and I'd like to get us started. If our first panel on Mammoths, Neanderthals, and Your Ancestors might come up, I'll introduce George Church who can then introduce them. So George Church is one of our own, a former professor of genetics here at Harvard Medical School and the principal investigator of the Personal Genome Project. He's the director of the Center for Causal Consequences of Variation and a member of the collaborating group for the Molecular and Genomic Imaging Center, both of which are NIH centers of excellence in genomic studies. He's written Regenesis, How Synthetic Biology Will Reinvent Nature and Ourselves. And you can get his full bio, which is really quite impressive, in your program too. So I won't belabor it. But thank you, George, for moderating the panel. -Thank you. I'm just going to do it from here. This is really one of my favorite topics. Every aspect of it, everything that we just heard just resonates. And it's very exciting to be on this panel. And I'm just going to moderate it. I'm going to try to get out of the way as quickly as possible. I don't want to repeat what's in your booklet. I hope you look it over. But I will say a few things that maybe aren't so obvious in there. And I'll go in the order that the speakers will speak. John Hawks has a massive online presence. This is his web blog. That's not a picture of John there. This is what he actually looks like here. But he has been involved in the Rising Star workshop. And for those of you who follow the Rising Star as a reality singing program, this is different. This is named after the rising star cave, which has a record for discoveries of our ancient human remains. He'll tell you about that, very exciting. And he has a-- he runs one of most massive the massive open online courses, or MOOCs. He got his PhD From University of Michigan. What's not in your thing, in your pamphlet, is he has a degree in English and French, in addition to anthropology. And he has a distinguished achievement professor of anthropology at the University of Wisconsin in Madison. He has some affection for Neanderthals. And I think many people have speculated about my relationship with Neanderthals. Full disclosure, I am 3% Neanderthal. And he's made a huge contribution to that level of understanding. Beth Shapiro, and I met I think because around 2007 I was mouthing off about ancient DNA, which she was a pioneer in producing progress in ancient DNA. And I was simply asked by journalists whether we could go from reading it to writing it. And I didn't have the common sense to dodge that question. Anyway, that led to us holding a meeting that Beth, a very tiny one at Harvard, really was the star and really made a big impression. And she has worked not just with passenger pigeon, but with mammoths, giant bears, camels, and horses, all the extinct large animals that stimulates us when we were young kids and ever since. I think this kind of field work is the stuff of Hollywood crusaders and so on. And she has this lovely book. I love the title, but I also like the cover. Because it not only has a mammoth and the words how to clone a mammoth, but a mirror mammoth and how to clone a mirror mammoth. So that's an inside joke, but anyway. And Spencer Wells has a really special place in my heart. In 2005, he was in the process without, I think as he would say without knowing it, founding the incredible field of direct to consumer DNA analysis in the form of the Genographic Project. And he's been an explorer in residence in the National Geographic, which I think all of us admire that sort of work. And he's led that project for 10 years. And we've already seen some slides from that. But about that time, I was involved in, a little after that, with 23 and Me and with the Personal Genome Project. And he helped us out in those early days of the Personal Genome Project. And he's written many books, such as-- here's one of the early ones I read before I met him 2002, The Journey Of Man. He's written two, the start, Pandora's Seed. He began his PhD when he was 19 years old here at Harvard. And then both he and Beth spent a considerable amount of time at Oxford. So without further ado, we will begin with John. Thank you. -All right, so here we are. I've just come from Gibraltar, where I was at a meeting with-- Gibraltar's a cool place for Neanderthals for lots of reasons. Most notably because of Gorham's and Vanguard Caves, which are some of the most important sites representing later Neanderthals, and really even up to the end of their existence. Last year at Gorham's Cave was announced the first known case of Neanderthals engraving on the walls of a cave. And so we now have the Neanderthal hash tag as a legacy of their social media savvy. It's a really exciting place, and I love going there. And the exciting part about this latest trip was that we had a meeting that involved some of the really big names in understanding Neanderthals and their contribution to our evolution. People like Milford Wolpoff, Chris Stringer, Erik Trinkaus, people that in the '90s were at each other's throats. Because they disagreed about almost everything fundamental about the way that modern humans originated and how Neanderthals did or didn't contribute to our populations. And the thing that was exciting about this last week for me is I put together, as a summary to the conference, a list of facts that now everyone involved in understanding human evolution universally agrees on. And the thing about it is that these facts are facts that have largely arisen through the application of ancient DNA technology to ancient fossil remains. It is hard to overstate the extent to which our present understanding of human evolution has emerged. Especially the later phases of human evolution has emerged within the last 10 years. And in large part due to our systematic investigation of the microscopic and submicroscopic aspects of fossils, including ancient DNA. So I thought that one way to talk about the way that we've changed our understanding of evolution by looking at ancient remains and the DNA in ancient remains is to go through this list. And I can tell you that the leading people in the field who have been leaders for 30 years last week saw this list and all signed off on it. So I tell you that this is really stuff that we now understand. So one is that living people today have Neanderthal ancestors. And many of you have heard that, of course, living Europeans, living East Asians, living Native American peoples have around 3% or so of Neanderthal ancestry. And peoples in sub-Saharan Africa don't have that kind of level. But nevertheless, because humans are all geologically hugely connected-- if you count back your ancestors, it doubles every generation back in time until it encompasses nearly the entire human population. Living sub-Saharan Africans have Neanderthal ancestors, even though their genetic component from Neanderthals is much lower. Living people today come in some small part from Neanderthals. But this contribution is regionally distributed among living people in surprising ways. So this is a chart that shows shared derived alleles with Neanderthals, so mutations people have in common with Neanderthals. And there's a lot of them in our genomes. But the difference between different populations is the signature that some of these populations have more Neanderthal than others. That's where we get this 3% figure from. And the higher you are in this chart, the more Neanderthal you are. East Asians, are more Neanderthal derived than Europeans. They have a little more on average. This is counterintuitive, because Neanderthals are known for being a Western Eur-Asian population. They're known best from Europe. So we've discovered that this population has a legacy. We've discovered that this legacy is not distributed as we might have anticipated. This is super interesting. DNA evidence has come from Neanderthals, not only across their European range. And these are all sites that have generated whole mitochondrial genomes of Neanderthals. And there's a few more now than when I made the chart. But also surprisingly across a Central Asian range that we did not formerly recognize as being Neanderthal central. We now think that this is the hotbed of Neanderthals. And that the European Neanderthal population was continually being replenished from this eastern source. But the other thing that we've begun to appreciate with the investigation of ancient remains that are less morphologically useful, the skulls and whole skeletons tell us immediately what something looks like. But most of the fossil record is fragments. And in particular, those fragments now are generating super interesting evidence about ancient populations. So this is Denisova Cave. I've had the privilege of going there are a number of times at the invitation of the Russian Academy of Sciences. It's a beautiful place with important excavations that cover the last 120,000 years of archaeological history. And this cave has produced in one little pinky an entire genome at what is now high coverage that tells us about the prehistory of a population that archaeologists did not suspect existed, a population that is as distinct from known Neanderthals as the most different living people are from each other. So there was an ancient population represented at this place, Denisova Cave. This aging population we've begun to call the Denisovans. And the Denisovans have contributed their genetic heritage to some human populations, largely the populations of Australia and Highland New Guinea, but in a very small fraction across most of Eastern Asia and the new world. So we've got not one, but multiple ancient populations that we've now sampled with ancient DNA. And they co-existed. We didn't expect this at all. And the idea that you would have bone fragments that were basically useless for any kind of morphological understanding create what is denser evidence of the heritage of an ancient group than we have gotten from most living people is just astounding. This is not only true of the Neanderthals and Denisovans. We can now look inside of human genomes and make some estimation of what we call ghost lineages, ancient populations that contributed to each other. If we look at my field guide to Pleistocene hookups, you will see that we understand quite an enormous amount about the contributions of different populations to each other in the past. The Denisovan population, which is known only from a pinky and two teeth, we know from looking at that genome has contributions from a mystery population, a ghost lineage of ancient humans, that separated from the main line of our human evolutionary history more than a million years ago, much more differentiated than Neanderthals, and Denisovans, and modern humans are from each other. We know from looking within the genomes of living Africans, using the same signatures that we recognize from ancient genes to recognize the contribution of ancient populations. We can now look for those same signatures in cases where the ancient genes don't exist. And we can find ancient African populations as differentiated as they are from living people, as Neanderthals are from living people, that have contributed to living African populations. Our evolutionary history involves many archaic and modern groups of humans that in every instance we have discovered interbred with each other and contributed to later populations, mostly to a minor degree. This is a very different picture of our evolution than we had in the year 2005. No one would have said that this is what our evolutionary history looked like. It's looking much more like a braided stream in which you have these populations that are separated for quite a long time, maybe with some minimal interbreeding between them. But populations that have become quite inbred, quite separate from each other. And sometimes later in time they come back into contact to contribute to each other. Sometimes of course, they must have gone extinct. This goes now back as far in time as 400,000 years where the earliest hominin nuclear and mitochondrial DNA has been recovered from a site called Sima de los Huesos, which is at the moment the most productive hominin fossil site in the world for producing skeletal remains of what we now recognize from DNA are fundamentally the ancestors of European Neanderthals. So there is so much to learn from these ancient specimens that we're now through technology being able to recover. All right, when we look at these ancient populations, I like this tree. It's a cluster. And it doesn't really recognize all of the complexities of this relationship. But it's a good measure of genetic difference. Because when we look at the known Neanderthal nuclear sequences, we now have a substantial additional sequence in this from the Altai. They are really homogeneous. There's very little genetic difference among them compared to the genetic differences among living peoples and compared to the genetic difference between them and the Denisovans. So Neanderthals are inbred. And when we look at particular Neanderthal specimens, this is a graph from a paper describing the Altai Neanderthal specimen, in some cases the inbreeding is profound. This individual was actually inbred. His or-- I believe it's a female-- her parents were in fact relatives and second degree relatives, something like uncle niece or grandfather granddaughter. This is highly inbred. And when we look generally at ancient human populations, including-- this is a chart that shows population size estimates over time, going back in the past. And the Neanderthals, the Denisovans, and in fact, the ancestors of most modern human groups have passed through very small stages where they were highly endogamous, highly inbred. It's something that we've learned from ancient DNA that every population that we know about that existed in humans before 40,000 years ago was much more inbred than living people are. We come from a heritage that is many small groups that were dynamic, that were continually limited in their genetic variability by the expansion and probably replacement of many small populations and the rejoining of these populations later in time. This point goes to address that. I mentioned earlier, we've got Neanderthal sequences from Central Asia and from Europe. What we now know is that the European ones seem to differentiate between those that existed before 50,000 years ago and those that existed after 50,000 years ago. And the ones later seem to have been replenished from probably a Central Asian source, as far as we understand the data. In other words, Neanderthals were not a static population that was sitting in Europe well adapted to the Ice Ages. It was a dynamic population. It was a population that ranged over large areas of space and continually expanded across them with groups replacing other groups. We're looking at human evolutionary history that is much more dynamic than we anticipated just by looking at fossil remains. Looking at the fossils, we tended to connect the dots and say as we go back in the past, what we're doing is we're linking ancestors and their descendants. What we now understand is that we cannot link ancestors and descendants in any direct sense. What we're linking is points along this very complex reticulate structure, some of which are separated for a while. And so maybe maintain a morphological contiguity with each other. But many of which are not particularly closely connected. Many of the things that we think in anatomical terms were probably important might be epiphenomenon of selection maintaining them over time within these geographic regions. When we go to more recent phases of our human evolutionary history, ancient DNA has been equal in its import. Although to my colleagues who are anthropologists working in human evolution, they haven't yet quite come to as good a grip of the importance of this. This is the earliest known modern European skull in Europe. It's from a Romanian site called Oase, which is deep in a cave that you have to get under water dive through to get to where the cranial remains are. When we look at Oase compared to-- this is a chart that shows its genetic similarity to Europeans at the top and Asians and Native American populations the bottom. You can see that this Oase individual is closer to the Asians than it is to Europeans. The first modern Europeans were not European. When you look at this skull compared to other ancient specimens, these are all ancient DNA specimens from slightly later phases of evolution, you can see that it's about equally related to them as it is to Asians and Native Americans. Our archaeological record of modern humans, the one that we thought was sampling the ancestors of today's Europeans, today's Asians, and so on, doesn't. It samples ancient populations that by and large have not contributed to great degree to any living people. This is a chart of the mitochondrial haplotypes found in the hunter gatherers that lived before the advent of farming in Europe. 83% of them have a haplogroup mitochondrial called haplogroup U. This is the same proportions of haplogroups in the first farmers in Europe. And as you can see, that haplogroup U, which was 83% of this population, is only 12% of this one. There are new haplotypes, including mine, haplogroup H, that arrived in Europe after the advent of farming. So Europe is a dynamic place. And we now have through ancient DNA time slices of this. And we can show that the ancestors that we once were thinking we're tracing our descent from these first Europeans actually have almost nothing to do with today's European populations. And Europe has undergone a succession of colonizations from other places. This is almost certainly not unique to Europe. This is almost certainly the history of recent humans, that our population has been dynamic. And the ancient archaeological remains that we have are by and large not the ancestors of living people. So of course, the other side of that is that once we look at ancient DNA remains, we can get a better resolution on how those ancient DNA remains are connected to living people. And through that process, reconstruct the ancestral populations. So this is some of the work from David Reich's lab here at Harvard. And you can see that there is a reconstruction here of where Europeans came from based on what we've learned from ancient genomes from Europe and from other parts of the world. And you can start to say that there were populations in the past that we haven't necessarily sampled well archaeologically that are source populations that have contributed to today's people through mixture. And we can start to get a picture of how those mixtures happened. This is all happening through ancient DNA. As a consequence, when we look at recent prehistoric humans, the kinds of cultural changes that we see-- I'm going to use the example of language shifts. But things like the advent of farming, things like the advent of the Bronze Age, the things that archaeologists have been trying to track for more than 150 years, those things we now recognize are in large part mediated by the growth and dispersal of relatively consanguineous populations. These are people that actually expanded and carried with them stuff, and the ways that they made things, and the languages they used. And of course, we've had this idea for a long time. Of course, many of you know the Proto-European as an ancestor of today's Indo-European languages is reconstructed to have originated somewhere in Central Asia. And we've studied the language shifts that have happened through probably the spread of these language groups. For example, the Celtic languages into Western Europe, the way that people must-- the way that languages must have moved and the Iranian languages of Central Asia and into India. We now can recognize that these sorts of phenomenon were actually mediated by people. The people were moving. And that phenomenon that we can see in recent prehistoric times was almost certainly the mode of dispersal of ancient people long before we have these kinds of archaeological records. Well, we've learned not only about the way that populations move and interact. We've learned about the way that these populations have changed through natural selection. One of the realizations that we have had, and I'm using slide of Tibet here to remind myself that, is that genes that we've gotten from these ancient groups sometimes are useful to us and actually make us able to do things that we wouldn't do otherwise. In Tibet, people are highly able to live at high altitude and to have more normal birth weight children at high altitude by function of changes to their circulatory system, changes to their blood. One gene involved in this, a gene called EPAS1, has an allele which is common in Tibetan peoples, which is very rare in nearby peoples in lowland China. And that this allele's most close relatives that we know of in anywhere, any archaeological or living population, are the Denisova genome. So we have here the origination of what is today an effective adaptation to a very unique extreme environment. We don't know the Denisovans were living in the highland plateau of Tibet. We don't have an archaeological record put in there. But we can say that the raw material of variation that came from this population was made use of in later humans to adapt to this extreme environment. We're in other words, changing as a function of interbreeding with these ancient people. It's useful to us in some cases. And of course, I am sorry I put up this table. But they did have a graph for this. And of course, we've been changing recently. And this is a great chart that shows it. These are three genes that are involved in pigmentation in human populations. And the one that I want to draw your attention to is all the way over here on the right side. This is the frequency of the light pigmented version of these genes today in the Ukraine. So this one HERC2, which is eye color related, has frequency today of 65%. This one SLC45A2, which is pigmentation related, is 92%. These are the frequencies in Ukrainian archaeological samples from around 5,000 years ago. You can see that these genes that make people light pigmented today are new. They haven't been around that long, and they've been growing in frequency during archaeological time. In other words, when we look at the past, the recent past, the past of a few generations ago, we're looking at people that in many cases are different from the people that are their descendants. And of course, there have been population movements that also contribute to those differences. But when we look over time, some things are becoming more common. Because they're useful, things like milk drinking, lactase persistence, things like genes related to pigmentation. We've discovered through ancient DNA the beginnings states of some populations in these. And you can see how the genes grow over time. Humans are changing. And it's a really exciting thing to think that we can see that happen now through looking at the ancient genes. Finally, ancient DNA is changing the way that we actually conduct archaeological excavations. And this is a great one. This is from a site called El Sidron. And this is my friend Antonio Rosas at the bottom, who's one of the main anthropologists working at the site. And you can see the guy in the bunny suit who is getting ready to go into this cave. This cave is a really constrained place. And you've got to work in this little place wearing this bunny suit. And he's got his samples that he's carrying out. We're actually really careful now about how we treat ancient remains knowing that some of the most valuable evidence that can come from them is DNA that, as I'm sure Beth will tell you, is highly fragmented, hard to get, and demands that we tried to eliminate, to the extent that we can, contamination sources. I've been recently involved in the Rising Star Project. And last month, we were fortunately able to announce the fossil remains that we've discovered, which now at more than 1,500 specimens are the most abundant fossil hominin site ever discovered in Africa. We named on this basis a new species, Homo naledi. There was some news about this. And so it's a really exciting thing. We're working in a very constrained cave, a cave where our team has to access the chamber with the fossils through a very narrow 18 centimeter wide crack that is a 12 meter free climb down to the bottom, that they have to wedge themselves down through. To do this kind of work, we recruited through Facebook a number of, where else would you find them, extremely skilled archaeologists who also have this kind of climbing and caving ability and also have the dimensions to fit through this very narrow chasm. And I'll tell you that there's all kinds of exciting things about this and the way that we work. But we're working in this fossil chamber that, at the moment, is a bed of fossil hominin bone. And our team is on bare foot protocol to make sure that they're not stepping on something. It gives them that sensory ability. Now, when I told my ancient DNA colleagues that I've got barefoot people walking through the cave to make sure that we don't damage things they started to scream. I mean, it was like, oh my god, the contamination. In fact, we do quite a lot to try to avoid contamination and collect samples that are collected in relatively sterile circumstances. And of course, technology has developed to the point where we can differentiate in a lot of cases the kind of modern contaminants from ancient DNA, actual endogenous ancient DNA. So we're pretty-- even our excavation conducted under relatively extreme circumstances is one in which we're changing practices to make it possible to get evidence from this ancient DNA source. You start seeing that take hold across a field, where people recognize the importance of it. They recognize universally what you're learning from it. And they recognize that this is contributing new information that they could not have gotten by any other means. And what it tells you is that we now have a field that's been transformed by the application of DNA technology. And it is hard to imagine where this is going to take us in the future. But if you told me 10 years ago that it would take us to the point where some of these real bold elephants of anthropology were all sitting at a table agreeing with each other about the basic facts, I would say that you were talking about science fiction. So ancient DNA has done more than contribute to our knowledge of human evolution. It's actually advanced the process of science by making us able to look at facts where previously we were working only with theoretical preconceptions. -Beth Shapiro. -Very impressive timing. -Yeah, that was amazing. -Make sure this is going to work, because I am too short to stand behind a podium. I've come to accept that. It's life, right? All right, so this is the past, present, and future of stuff. So I thought I would start by just talking about the past, present, and future of this field that I work in, that John so very nicely gave a overwhelmingly supportive introduction to. Let's see. I will get to cloning mammoths, but it will be toward the end in the future section. Because we haven't done it yet. Although, George is trying very hard. So ancient DNA, it all started way, way back in the early 1980s when a team of researchers in Allan Wilson's lab at Berkeley, they called themselves the extinct species study group, extracted in sequence the tiny little fragment of mitochondrial DNA from the skin, museum preserved skin, of this guy. This is a quagga. They were able to sequence a little bit of DNA from this thing. And wait for it, it turns out it's related to the zebra. So it wasn't exactly a overwhelming exciting scientific result. But the idea that DNA was preserved in things after they died was new. And this was pretty exciting. It actually set off a whirlwind of research. People started to extract DNA from pretty much everything they could find. There were mummies that had DNA in them, probably. There were Miocene aged leaves. And before we knew it, there were dinosaur DNA sequences being published from things that were entombed in amber. The problem with all of this stuff is that it wasn't real. We come to know now despite being published in very high profile journals there were quite a few papers that should have been retracted. I don't think ever have been retracted. But everything about dinosaur DNA, for example, is not true. And the reason is because DNA does not last forever. As soon as an organism dies, the DNA that's within all of its cells starts to break down into smaller and smaller pieces. One of the things that causes this DNA decay is the sun. So when we're alive and we go outside, the sun, UV radiation from the sun, hits our cells and actually breaks our DNA. But we have proofreading enzymes that will go along and fix this damage. So we don't get cancer every time we walk outside. Of course, these are all energy requiring processes. And after you're dead, you no longer have any energy, so UV radiation, oxygen, water, enzymes that are in microbes that are in the gut. If the gut bursts during decay, all those microbes go circulating around the body, starting breaking down that DNA into smaller and smaller fragments. Also tons of microorganisms in the soil. When these fossils are sitting in the soil, these microorganisms will colonize the bone, break down the DNA into smaller and smaller pieces until eventually DNA, which when you're alive you can think of as these massive long strands of party streamers, look more like confetti. But not really attractive confetti like this, like the confetti from the New Year's parade that emerges after the last snow melts in the Kmart parking lot in April, or May if you're in Edmonton, as many of my friends are. So yes, DNA degrades. And this process will continue at a rate that depends on where the bone is actually preserved in cold and dry places. Or cold places that are pretty much temperature stable, the DNA lasts for longer than it tends to last in warm and hot places. And today, the oldest DNA that is known comes from this place where I spent a lot of my time outside of Dawson City in Canada's Yukon territory, where we find all of this frozen sediment that's up there. And this oldest DNA is about 700,000 years old. The reason that we know it's that old is because in places like this part of the world, we find these volcanic ash layers. This white layer here is actually from an eruption, a volcanic eruption, that happened. This particular eruption was about 80,000 years ago. And we know that by dating it using different methods like thermal luminescence dating. So we found this particular bone, this 700,000 year old bone, in association with an ash layer from an eruption that happened somewhere around 680,000 or 700,000 years. So we know how old this bone was. And the DNA in this bone was in terrible condition. There was very little of it. It was highly damaged and highly fragmented. But we were still able to generate enough data from it to sequence a complete genome of a horse-- it's just a regular horse, the kind of horse that still lives all over the place today, Equus caballus-- and start to learn about how horses had evolved and changed through time. Now, 700,000 years is a lot more recent than 65 million, or 85 million, or even 100 million years, which is how far back we have to go to get dinosaur DNA. So for the time being at least, Jurassic Park, at least as it was in the mind of Michael Crichton and the many writers, and producers, and directors who continued this chain of fantastic blockbuster scientific films, will remain a thing of science fiction. Sorry. But it is not all sadness. And there are some incredibly well preserved remains that are found. And that we now know have quite a lot of DNA in them. That mummified mammoth that you see up here in the corner, this is one that was found up in the New Siberian islands a couple of summers ago that was thought to be associated with blood. It was of a thick red, black, viscous substance. That I'm told they've discovered now was not blood, but instead what is officially known as corpse juice. Nonetheless, whether or not it's blood or corpse juice, this is an incredibly well preserved specimen. And we are able to extract and sequence DNA from these things. So the field is called ancient DNA for obvious reasons. And as I explain it now, I'm just going to go through a little bit, a short history, of different parts of it, my involvement with ancient DNA really in the past and the present and then get to the future. So the past of ancient DNA is not very long. I started working in ancient DNA in 1999. I was at Oxford University in Allan Cooper's lab. We were one of the only labs at the time that were really focusing on extracting DNA from ancient remains. So it was pretty lucky that we got in there at this time. I work mostly in a part of the world called Beringia. This is Beringia here. It spans Alaska, the Yukon territory here, across the Bering Strait and into-- that's the part of the world that Sarah Palin, remember her, can see from her backyard. It's too bad she's not involved in this particular race yet. Isn't it? No it's not. Do you see that the sea level here? This light coloration here indicates the sea level is a lot-- it's shallower there. And so during the Ice Ages when a lot of the water on the planet was taken up into forming massive glaciers that it sat on top of the continents, the sea was lower than it is today. And this was actually exposed. It was a very important land bridge for the movement of plants and animals between the continents. And we had lots of movements. Horses and camels moved from North America into Asia. Bison, things like that, humans moved from Asia into North America. It was a really very important conduit. Today, Beringia looks a lot like this. I'm in this-- I'm taking this picture from this lovely helicopter. This is in the Taimyr Peninsula in North Central Siberia. I'll show you the helicopter in a minute. Because it's awesome. But in the past it looked more like this, where there was a rich diversity of plants and animals and included things like mammoths, and mastodons, and woolly rhinos. They never made it into North America, but they were pretty abundant in Siberia. There were a couple different species of horses in North America. There were crazy things like giant bears that if stood up like this would be 15 16 feet tall. We killed them. My favorite extinct animal, the giant beaver, my size beaver. It's just the funniest extinct animal. And so we go out into these places. And we fly in these stellar machineries. I told you I was going to show you a picture of this. You'll notice that there is actually some glass missing from some of these windows, which is really good. Because these gas tanks here that take up most of the inside, that's where we sat. And after we took off and celebrated the fact that we had gotten off on the air, some of the people who were sitting on these gas tanks decided that smoking was a good way to celebrate. So at least we had the windows to let the cigarette smoke out. We stay in five star accommodation. That's my tent. I took this picture by backing up and unfocusing my camera. So you could see the depth of field of mosquitoes that we would deal with there. And we wander along collecting bones. This is actually from near Dawson City in the Yukon. There is active gold mining going on there called placer mining where these miners are washing away this frozen dirt to try to get to the gold bearing gravels that are beneath. But as they're doing that, thousands of bones, really well preserved bones that look like they could be a couple years old or even modern, come out of this. And we walk around and collect them. In an average day of working up there, we can collect something like 30 or 40 bags that look like this. Those are mostly horse, bison, reindeer, and mammoth bones. But when we get lucky, we get a carnivore. They had smaller populations, but we can still find them, sometimes wolves and bears, giant bears. We take a chunk out of each of these bones and take them back to the lab. And we can do this over time. So we know how old all of these different bones are. And we measure the amount of genetic diversity that's in these populations over time by extracting DNA and sequencing a bit of that. And then we can use those measures of genetic diversity and a statistical approach called coalescent theory to translate diversity into population size. And so we could come up with these plots of how populations changed in size, a big population sometime in the past going to a smaller population in the present day. And we've generated population level data sets, hundreds of individuals, for about a dozen species so far. And here's just four of them to give you a taste of what we can learn. The top graphs with the colored background show a reconstruction of how much habitat was available to these animals over time. And this time scale goes through the last 50,000 years. The tick marks here are the fossils, the dates, that we use to make these reconstructions. So the top line is the amount of habitat that they had. And then this lower line with these confidence intervals around it are how big their populations are. So you can see from this that as the amount of habitat available to each of these species increases, so do their populations. And as the amount of habitat decreases, so do their populations. So these animals are really responding opportunistically, dynamically to the amount of stuff that's there for them to eat. You notice that none of the species that I've put up on here-- and you'll notice with these stuffed toys here, you can clearly see that this is horses, bison, caribou, and musk ox. None of these are extinct. That's because when species are extinct, it's very hard to reconstruct their population dynamics. What we found in doing this work is that as populations declined toward extinction, we didn't see a decline in genetic diversity. What instead we saw was that we were seeing an increase in the amount of genetic distance between individuals. So what it looks like is happening as species approach extinction is the habitats are becoming more and more patchy. And individuals are getting stuck in these patchy habitats. And then all of these patchy habitats are declining simultaneously. So this approach of looking at one genetic locus or two genetic locus and trying to find out when extinction is happening in this way doesn't work in the case of these types of animals. Fortunately, we have moved on to the present day where we don't have to use these one locus or two locus analyses anymore. Because instead, we have this crazy type of new sequencing technology that lets us see every little bit of surviving DNA in these bones. We call this next generation sequencing. This is one of the fancy machines that you can buy for around $1 million and go out and sequence a whole bunch of DNA. And this has been absolutely fantastic for ancient DNA. Will people working with modern DNA complain a little bit about these machines, because they can only sequence short fragments of DNA at a time? We don't care at all, because we only have short fragments of DNA. And for this reason, Alumina like to parade me around when they're doing their sales pitches as the person who goes up and says this is a great machine. It does everything I need it to do. Absolutely everything, nothing wrong with it whatsoever. So the kind of things that we can do-- and here is just a plot. This is a paper that we published recently, a couple weeks ago. This is a plot from some bones that we collected in the Arctic. They're about 120,000 years old. And in the early 2000s, we tried to extract DNA from them and amplify them up using the traditional way. And we found absolutely nothing. We couldn't get any DNA out of these bones whatsoever. And they're cool bones, because they belong to a really interesting species that I'll show you a picture of in a minute. So we decided we would go back to these bones now using this new next generation sequencing technology and see if there is DNA in there, just two short fragments of DNA to be able to amplify using the traditional technologies. And it's true. This is the fragment length distribution for these three bones. You see that the mean fragment length of them is around 30 base pairs long. That's not just confetti. That's like the punch holes from the pieces of paper that you would get to throw up in the air. Normally we get millions of bases at a time, 35, again, and somewhere around 30. These are terribly preserved. The bottom plots also show that the ends of each of these molecules have typical types of damage that you see in ancient DNA. And this is a really cool thing that this next generation sequencing technology lets us see too. And gets back to what John was saying about how we can tell the difference between modern DNA contaminating DNA and the real ancient stuff. Modern DNA doesn't have this damage. But ancient DNA does. So if we have a bone, a human bone, that we know has human DNA in it, the first thing we can do is only look at the molecules that have this signature of damage. And that will exclude, for the most part, the contamination that's in there. So this particular individual, this species that we were interested in, is the North American camel, Camelops hesternus. And it was a long paleontological mystery, which kind of camel this thing was most closely related to. New world camels, which are lamas, and alpacas, and vicunas, things like that, or old world camels, the dromedary and Bactrian camels. Most people thought it was new world. Turns out we have this paleontological information from aging DNA. That in fact, they are more closely related to old world camels than new world camels. So it's not as exciting as humans have-- there's a new human. But camels are interesting. Other things we can do with ancient DNA-- I'm just going to do one more thing to try to give you just a taste of what we can do after we have these ancient genome-- is study the consequences of the evolutionary consequences, genomic consequences, of different processes. And one of these is domestication. We had a paper last year where we looked at the process of horse domestication. So ancient DNA on these orange things are ancient horses. The blue ones are modern horses. These are the Przewalskis, which is a wild modern horse. You see that according to mitochondrial DNA there is a ton of diversity in horses. A lot of horse females were presumably used in the domestication process, but very few males. We have nuclear genomes now from a couple of different horse genomes. And because there seems to be a lot of-- there seems to be a mixture between these wild horses and modern horses. We can't learn about the process of domestication looking only at modern DNA. So we sequenced complete genomes from a couple of horses that we know were not domestic, because they lived before domestication happened. And were able to then scan through their genomes using a variety of approaches and identify parts of the genome that look like they have been under selection since domestication. These are the genes that were the product of the domestication process. And we found a lot of different things that we expected to find. We found genes that have been associated with different behavior, being nicer, being calmer, being tamer. Genes associated with pigmentation, we knew that these genes were under selection and domestication. And genes associated with their agility, ataxia genes, et cetera. We also found a whole bunch of things that we don't know what they do. So the next step in this is to try to use different types of experiments and make these genes express in tissue culture and figure out what's going on. So ancient DNA can show us where to look to better understand different evolutionary processes. And now on to the future. So what does the future of ancient DNA have for us? So we study a lot of different things in my lab. We study all of these large mammals that used to live during the Ice Age. We study domestication. We study adaptation to climate change. We try to better understand how populations and species responded to changes to their habitat that were associated with the last Ice Age. Because we want to be able to make more informed decisions about how to use what limited resources we have today to preserve species in the face of predicted climate change. And often when we publish these papers, because they're about big mammals that people think are fun, we get some popular press coverage for these things. And people call. And I'm always really excited to talk to people about the kind of cool and interesting science that we're doing. But they really only ever want me to answer one question. And so to answer this question I wrote this book, which basically says no, not yet. And I'm not going to go through a lot of the details in this book anyway in this talk right now. But in the book I do go through the technical challenges associated with bringing a mammoth back to life, as well as talk about some of the ethical and ecological questions that are going to come about. Of course, it would be remiss of me since I'm standing here not to highlight some of the really cool stuff that is being done there, in particular by this motley crew of-- are you wearing the same thing? These guys have been doing-- and I'm sure we're going to get a chance to talk about it when we have the discussion section here. But they have been doing some fantastic work, at least to set us off on the right foot to figure out what we would need to do if we were going to bring a mammoth back to life. I think one of the most important things to remember when we think about bringing a mammoth back to life is that the Asian elephant and the woolly mammoth, Asian elephants are known to be the closest living relative of woolly mammoths, are separated from each other by somewhere around 5 to 7 million years of evolution. And this is not very much. This is not very much change. So when you look at an Asian elephant, you're actually looking at something that is about 99% mammoth already anyway. So if you're going to take an Asian elephant and turn it into a mammoth, all you have to do is identify that last 1% and change that. 1% of 4 billion or so base pairs is still like a million and a half changes. But he's a pretty smart guy. I'm sure we can figure out how to do this. We're also having-- we're getting a much better understanding of the types of differences, the types of genetic changes we might need to make. One of the first discoveries that differentiated mammoths and Asian elephants came from Kevin Campbell's group in Manitoba. They were looking at hemoglobin, a protein that is a part of the red blood cells. And they discovered by sequencing hemoglobin from elephants and mammoths that part of this gene-- it's made up of several genes. But part of it was different only by three different changes. Three nucleotide changes led to three different amino acid changes. So the protein sequences in hemoglobin were really similar. They wanted to know though, what's up with these three changes. Why are these three changes actually important? And so they expressed these genes and measured their ability to carry oxygen around the body, this is what hemoglobin do, in different types of environments. And they found that the woolly mammoth version of hemoglobin was much more efficient than the Asian elephant version at carrying oxygen around the body when it's cold. Pretty good. So this is obviously one of the adaptations that occurred along the lineage to woolly mammoth since the divergence between woolly mammoth and the Asian elephant. So George and his team are looking through these genomes now. There are a whole bunch of genomes that have been published recently for woolly mammoths, as there are a lot of genomes that are becoming available for Asian elephants, and making lists of the genes that are different, and trying to figure out whether they're important or not. And then using CRISPR technology, which we'll hear about later, to try to swap these genes out, cut and paste your way from an Asian elephant into a woolly mammoth. So why might we want to do this, just a little end on why we might want to go through all of these problems considering there are major technical, ethical, and ecological hurdles that we will encounter along the way to doing this? In the purpose-- for the case of mammoths, there are really two reasons that are discussed. And the first is ecological. There is a place in Northeastern Siberia that's led by a guy in the Russian Academy of Sciences called Sergey Zimov. And he calls this Pleistocene Park. Pleistocene was much more recent than the Jurassic, so well within the realm of possibility here. Pleistocene Park is a great and exciting place. And Sergey already has introduced into Pleistocene Park a couple of different big animals that are reminiscent of the Pleistocene, the Ice Ages, where we had things like mammoths and mastodons. He has bison from North America, about five different species of deer. There are some horses that he's introduced to this area. And he's shown that over the course of just a few summers that just having these large mammals on this landscape, just their presence alone, has been enough to reestablish this rich grassland that used to be part of this landscape in Siberia. Just having these animals there churning over the soil, distributing nutrients, distributing seeds makes the grass come back. In essence, they provide their own habitat. And he's also seen that other species that are in danger of extinction, because their habitat is declining, like the saiga antelope, have started visiting the park. This is a picture of his park. Over here on this side, he has the animals. And he has them fenced out over here. You see that this is actually-- you can't see it very well, the colors here. But there is some green little patches of green all around here. And they're actually very different. It's much more speciose, more biodiversity, than you get on this particular side where you don't have animals. This is also early spring. And this means that there has been enough grass that some of it is still surviving this harsh Siberian winter. So these guys really are ecosystem engineers and bringing these animals back, this large herbivore. I mean, elephants play important fundamental roles in their ecosystem in Africa. There's no reason to assume mammoths didn't do the same in Siberia. So he argues, Georgia argues, and I would argue that bringing back these large herbivores will help to reestablish interactions in this ecosystem that have been missing since their disappearance. And the same argument could be made for many other extinct species. Not to bring them back just for the purpose of looking at an extinct species and seeing it in a zoo, but to reestablish interactions in ecosystems that have been missing since the time of extinction that perhaps can be used to reinvigorate that ecosystem and save living species, which is actually the second reason. This research is not only teaching us about what Asian elephants might have done or might have looked like. But it's teaching us about elephants. And Asian elephants are in danger of going extinct. What if we could use this technology to take some of these genes that have been shaped by evolution in past to reinvigorate the diversity, the genomes, the survivability of species that are in danger of going extinct today. If we could take an elephant and give it the capacity to live in colder climates, we could expand the range that an elephant could live in. Saving elephants, rather than bringing mammoths back to life. So I'm going to leave it there. But we can talk about the ethics, and ecological challenges, and technical challenges later. But for now, thank you very much. -Wow, what an amazing time to be a scientist. If you had told me 10 years ago that ancient DNA labs would routinely be producing the data they're producing today, I would have laughed you out of the room. So it's really incredible to see how the field has progressed. But let's step back. Let's think about modern humans, which is what I'm going to talk about. And let's think about this whole issue of human migration patterns, and in particular, why humans are dispersed so widely around the earth, and why we're so diverse. Put yourself back in time, European age of exploration. You're cruising around the Pacific with Captain Cook at the end of the 18th century. And every time you crash ashore on one of these remote islands, you find people there. And they're somewhat like people you've seen before, but different in some ways. The language is slightly different. They may look a little bit different. Why are people so widely dispersed, and how do we account for the diversity that we see? We see a dizzying amount of phenotypic diversity, facial appearance and so on. That's really the overarching problem in the field of human population genetics. And like any big overarching problem or theme, you can break it down into sub themes or questions that we can start to chip away at using the tools of science, gathering data, formulating hypotheses, coming down on one side or the other. First question we can ask is one of origins. Are we in fact all related to each other? And if so, how closely? And the second is one of journey. If we do spring from a common source as a species, how do we come to occupy every corner of the globe in the process of generating these patterns of diversity that we see today? Well, the question of origins, as with so many other big questions in biology, seems have been answered over a century ago by Charles Darwin. He wrote in his second most famous book, The Descent of Man, "In each great region of the world the living mammals are closely related to the extinct species of the same region. It's therefore probable that Africa was formerly inhabited by extinct apes closely allied to the gorilla and chimpanzee. And as these two species are now man's nearest allies, it's somewhat more probable that our early progenitors lived on the African continent than elsewhere." OK, so Darwin solved the origins problem. Except he didn't really. He of course, is talking about our shared ancestry with apes. And he was absolutely right, even though he didn't have any data to support that at the time. We now know from the fossil record that apes do appear first in Africa around 23 million years ago, the great apes. At a time when Africa was actually disconnected from the rest of the world's land masses due to plate tectonics. It bumps into the Arabian Peninsula between 16 and 18 million years ago. And at that point, we have the first so-called African exodus. The apes that left at that time and ended up in Southeast Asia ultimately evolved into the gibbons and the orangutans. And the ones that stayed on in Africa ultimately became gorillas, and chimps, and yes, us. So yeah, Darwin's absolutely right. If you go far enough back in time 23 million years, you find that humans are an African species in common with all other great apes. But that's not really the question I'm asking. Rather I want to know about us as a species, Homo sapiens, individuals that we would recognize as being like us if they were sitting out here in the seventh row. That question has been approached historically through the study of paleoanthropology, going out and digging up bones and saying typically on the basis of morphology, often skull shape, this looks a little bit more like my cousin Frank than that does. This is the missing link. This is where we all came from. What I would like to suggest though as a geneticist who values large amounts of data is that while the field of paleoanthropology gives us lots of fascinating possibilities about human origins and dispersal patterns, it doesn't give us the probabilities about direct lines of descent that we really want unless we're lucky enough to get ancient DNA out of them. Possibilities about our past and our origins, but not the probabilities about direct connections to those individuals. This is a great example. What you're looking at here are three extinct species of hominids. From left to right, Homo habilis, Homo erectus, and paranthropus boisei, robust australopithecine, all uncovered from the same location in northern Kenya and all dating to roughly the same time, about 2 million years ago. So which one of these guys am I actually directly related to, descended from? I don't know. Possibilities about our past and our origins, but now the probabilities we really want. Well we as geneticists of course, take a slightly different approach. We turn the problem on its head. Instead of digging things up out of the past and guessing at how they may or may not connect to the present and to us, we start in the present. And we work our way back in time. Because we know it's an absolute certainty that everybody alive today had parents. And those parents had parents and so on. So it should be possible to build a family tree for everyone alive. And I'm sure that a few people in this room have done that, built a genealogical tree. It's the second most popular hobby in the country after gardening. Told it's poised to overtake gardening very soon. But no matter how far back you can trace your family line and ultimately it all ends at Charlemagne for some reason if you're from Europe. The point is that you eventually run out of the written record about your ancestors. And we simply enter this dark and mysterious realm we call history, and ultimately prehistory. But it turns out, of course, that we're all carrying a written historical document inside of ourselves, inside of nearly every cell in our body in our DNA. And that allows us to see back beyond that brick wall, as the genealogists call the place where the records stop. Back to the very earliest days of our species. And we've already had a bit of a primer on DNA. But just to reiterate, long linear molecule, the famous double helix described by Watson and Crick in 1953 composed of four subunits-- A, C, G, and T. And it's the sequence of these A's, C's, G's, and T's that basically provides a blueprint to make another version of yourself. And in every generation, you have to copy all of this information to pass it on to your kids. And it's a lot of information. There are billions of A's C's G's and T's in the human genome. And so it's like copying a very long text. Imagine a long book. Say, War and Peace. But it's like copying 1,000 volumes of that. And you've got to do it in eight hours, which is roughly what it takes with yourselves to replicate your genome. And this is really important information. So what are you going to do? Well, you're going to get your cup of coffee, or whatever it is that keeps you focused. And you're going to check and double-check very carefully as you're copying all of this information, because it's so important. But inevitably, what is going to happen as you're copying? You're going to make a typo, a spelling mistake. Those happen at the DNA level as well during this copying process, at a rate of around 100 mutations, as we call them, per genome per generation, as the DNA is being copied to be passed on. And as these mutations get passed down to children, grandchildren, great-grandchildren, they become what we call markers of descent. So if you share one of these changes, one of these markers in your DNA, with another person, that means you share an ancestor-- the person in the past who first had that mutation in their DNA and passed it on to the two of you. This is actual DNA sequence data. Old-fashioned Sanger sequencing, which is still the gold standard for clinical diagnostics. Five individuals-- one, two, three, four, five-- have had the same region of their genome sequenced. They've been lined up. The first thing you'll notice as you read down through these sequences is that they're basically identical. In fact, humans are 99.9% identical at the DNA level. We only differ, on average, at one in every thousand nucleotides positions from someone we're not even closely related to. So it's actually quite difficult to find these genetic markers. But if you look carefully enough, down here in this region, GGGG GAG. A single letter change from a G to an A, that's a marker. If you share that with another person, you share an ancestor-- the person who first had that change and passed it on to the two of you. And by looking at the pattern of these markers in people from all over the world, focusing in particular on what you heard about earlier-- mitochondrial DNA, the Y chromosome-- we've been able to construct family trees for everybody alive today. Everybody in this room-- in fact, everybody walking around on planet Earth all 7.2 billion of us falls somewhere onto one of the branches of these trees. Now, these are very, very simplified versions of the assays we actually when we're designed in the essays in the laboratory. But they still look complicated, sitting out there in the audience in the morning. So let's simplify them, combine them, turn them on the sides so the roots at the bottom and the branches are at the top like a real tree. What's the take-home message here? Well, it's that the longest branches in the human family tree, the branches with the most mutational changes in them, if you will, are found only in African populations. And what that means is that because of this molecular clock-like process, the mutations ticking off at 100 per genome per generation, Africans have been accumulating genetic variation for longer than any other group. And, therefore, our species originated in Africa. And at some point in the past, a small group carrying a subset of African diversity set out to leave Africa and colonized the rest of the world. OK. So we're back where Darwin started. Except we're not. We're not talking about 23 million years ago. We're talking about an event that happened within the last 200,000 years, which is in agreement with the fossil record. Modern humans first appear at Omo Kibish in Ethiopia, 195,000 years ago. That's roughly the coalescence point for mitochondrial DNA. And it's only in the last 60,000 years-- 2,000 human generations-- that we've set out to colonize the rest of the planet. An early coastal migration leading very rapidly to Australia. Later inland migrations moving to Europe, crossing the Bering land bridge into the Americas-- the great paleolithic wanderings of our species. And it's really detailing these migration patterns. That's been the goal of the Genographic project over the course of the last decade. Now, what is Genographic all about? You referred to it earlier. Thank you very much for the intro. At its core, it's a research effort. It's an effort to make sense of the human journey, the human story. And this is field research that's being carried out by a consortium of scientists around the world, working primarily with indigenous people, world's traditional and indigenous groups. Now, why are indigenous people so important to this effort? Well, think about your own ancestry. I'll think about mine out loud. I have ancestors from all over northern and western Europe. I lived until very recently in Washington, DC. Just recently moved to Austin, Texas. What does my DNA tell you about the ancient patterns in any of those places? It's hard to say, because I'm a mutt. And I've moved around a lot recently, or my ancestors have. Ideally, we want people who have lived in the same place for a long period of time, thousands, tens of thousands, even, in the case of Africa, hundreds of thousands of years. The world's indigenous and traditional people. And they give us that glimpse of the ancient genetic patterns linked to a particular geographic location that allow us to make sense of these human migrations. But when we were designing the project, I felt very strongly that it should not just be the story of the world's 100, maybe 200, million indigenous people. It's the story of all of us. All 7.2 billion. So we wanted to open it up to members of the general public who were interested in testing their own DNA, getting the results back, but also joining the project, increasing the size of the database, giving us more power to detail these migratory routes. So the public participation side, a very important component. By selling the kits we help to fund the research we're doing out in the field with the indigenous populations, who, obviously, can't afford to buy a kit. And also, the third component, the legacy fund. This is a way to give something tangible back to the world's indigenous and traditional groups, many of whom are leading ways of life that are endangered today. They're often forced to leave behind their ancient villages, their homelands, typically moving to a growing megacity. They become part of the melting pot. Their kids stop speaking the original language. They lose the culture within a generation or two. We're actually going through a period of cultural mass extinction at the moment that parallels the biodiversity crisis. Linguists tell us that of the 6,000-some-odd languages spoken on Earth today, by the end of this century, between half and 90% will be extinct, no longer spoken. We're losing a language every two weeks. So through the legacy grants, we want to do something to raise awareness about this, and if we can, to slow it, or even to halt it. Well, how are we doing? How have we done in the project? Well, an easy way is to look at numbers. On the indigenous side, we've sampled roughly 72,000 people representing over 1,000 different populations from every inhabited continent. Not Antarctica, obviously. Published more than 50 scientific papers. Have several more in the pipeline. So that's gone very well. The big surprise, though, for me, has been the excitement on the part of the general public in getting their own DNA tested. When we were designing the project, I had a bet with the then-CEO of National Geographic, John Fahey, about how many of these kits we were going to sell. He said, Spencer, if you sell 1,000 of these things in the next few years, you'll be lucky. Nobody's going to pay $100 to get their DNA tested. I said, I don't know, John. I don't know. I think there's something to this. The day we launched the project, 10,000 people ordered kits. And we hit 100,000 eight months later at the end of 2005. And we're up to around 700,000, now. More than 140 different countries. We've even sold two to Vatican City. Very curious about those two. And it's raised a fair amount of money, obviously, for the field research, and also the legacy fund, which we've given away $2.5 million so far. Just some examples of projects that we've funded. Project to save the Yaghnobi language, the last remnant of ancient Sogdian, once the lingua franca of the Silk Road. If you had gone to Bukhara or Samarkand or Kashgar 1,500 years ago, you would have been speaking to the merchants with this language, now spoken by around 1,500 people who, historically, have lived in the remote Zeravshan River Valley of northern Tajikistan. Most have now been resettled to the capital, Duchanbe, and their kids learn to speak Russian and Tajik. And so the language is literally on the verge of extinction. We're helping to fund school curricula in the Yaghnobi language. Project to preserve a traditional dance pattern among the aborigines in the northern territories. Their song lines, their stories of where they came from. A project along the Yukon River, an intertribal collaboration with tribes from Northwest Territories in Alaska to raise awareness about the environmental issues that are affecting, in particular, the salmon population there, which is so important their way of life. And this is a great example for people who need a practical reason for saving this information and these cultures. The Shuar people trying to preserve their ethnobotanical knowledge. Now, how many people have been prescribed a medication by their physician recently? Probably most of us. And about 30% to 40% of those ultimately trace back to plant sources. We often know about these plant sources because of accumulated traditional knowledge. Tens of thousands of years by thousands of populations experimenting with their environment, learning which plants do certain things and which don't. When we lose that body of knowledge, how many potential treatments for cancer or Ebola or HIV might we be missing out on? We don't know. But I think it's worth preserving. So I'm often asked, what's your biggest surprise? What's the most surprising thing that's come out of the project? And there are scientific discoveries, ranging from populations fissioning off in Africa long before we started to leave and headed toward becoming separate species, or the genetic impact of Ghengis Khan, whatever it might be. But the big surprise for me has been the excitement on the part of the general public in getting involved in this project. In particular, the power of what we call citizen science-- non-specialists getting actively involved in the research project. And I've got a great example. This came to light by accident a few years ago. A woman writes into the project and says, love what you're doing. Lots of members of my extended family have taken part. We've told lots of people about it. It's very, very exciting. So cool. However, it seems like you got my results wrong. And I'd like you to retest me. Because what you've told me is I'm carrying a mitochondrial type that's common in Central Asia and Siberia. And I know for a fact from the genealogical records that my family came from a little village just outside of Budapest, which you're looking at here in Hungary. So clearly, I've got to be European. I can show you records going back to the 16th century. Please retest me. Thank you very much. Now, when I heard about this, I got really excited, not because I enjoy asking the lab to cherry-pick one sample out of 3/4 of a million. They tend to get a little annoyed about that. But rather, because the Hungarians have a fascinating history. Linguistically, they're very different from other groups living in Europe. Most of Europe's languages fall into the Indo-European language family that we heard about before. A Western Eurasian collection of languages that includes the one I'm speaking now. Part of the Germanic branch of Indo-European languages. Romance languages-- French, Italian, and Spanish-- the Celtic languages, the Slavic languages, and so on, all parts of the single language family that probably originated somewhere in the southern Russian or Ukrainian steppe 6,000 to 8,000 years ago. And the languages have diversified over time. Except there are a couple of languages in Europe that don't fall into that category, into that family. One is Basque, which is what we call a linguistic isolate. It's unrelated to anything else on Earth, as far as we can tell. It could've been brought here from Mars. Might be distantly related to ancient Sumerian and some of the languages spoken in the north Caucasus, like Daghastani, but it's very, very tenuous. OK. That's off on its own. Hungarian is a member of a different language family. It's related to languages spoken in Finland, in Lapland, the Saami languages of northern Scandinavia. All part of what we call the Uralic language family. And as you can see, most of the diversity in that family lies over in Siberia. And this makes sense, because it's believed that the ancestors of the Laplanders, the Saami people, migrated into northern Scandinavia from Siberia within the last 5,000 years, bringing with them their language that belong to this Siberian group. We also know from historical sources that people from somewhere further east-- the Magyar people-- around 1,000 AD migrated into central Europe, settled there and created present-day Hungary, bringing with them their culture, their love of chicken paprikash-- that actually came later, because peppers, of course, come from the new world. But anyway, the Hungarian language. So they had a massive cultural impact on central Europe. And so geneticists, using this as a guide-- and we often use linguistic patterns as a guide when we're thinking about the sampling-- went in and sample the number of people you typically study in one of these projects. 50, 75 people. And what they found is that the Hungarians are identical, essentially, genetically to the surrounding non-Hungarian speakers. You don't see any genetic evidence for this huge cultural shift. So when this woman wrote in to us, I said, well, here's an opportunity to see if this public database is actually useful. We don't have to limit ourselves to the scientific sample sizes. How many samples do we have in the database from people with Hungarian ancestry? Well, we had 2,300 at that time. And lo and behold, we found that 2% to 3% of the lineages on both the male and female side were coming out of Asia. So that makes sense. Power of large numbers. We knew that was going to be something cool about creating this large database. But the only reason we knew to look for this pattern is because this woman wrote in to us. And that is the power of citizen science. Instead of having a few scientists sit back and say, these are the important things we should be studying, we dispersed that out into the community. And you've got, effectively, hundreds of thousands of scientists, now, who are looking independently at their own data, trying to make sense of it and finding patterns like this. And building that kind of citizen science functionality into the project has been a very important part of the relaunch that we did a couple of years ago in the creation of Geno 2.0. I'm going to end by talking a little bit about consumer genomics. And I despise the term direct-to-consumer genomics, because we don't talk about direct-to-consumer bookselling. Direct-to-consumer implies that there should be a mediator that's making decisions for you. And I feel very strongly that genomic information should be available to anybody who wants it. I want to talk a little bit about how the industry has progressed. And it's really reflected in this graph. These are number of people who have bought kits, DNA testing kits. So the industry traces back to around 2002, when Bennett Greenspan founded Family Tree DNA down in Houston, primarily because he was interested in looking at his Y chromosome to see if he is a descendant of Aaron, carrying the Cohen modal haplotype. And I'm not going to go into the details on that story. But there is very, very good evidence that you can find a genetic pattern that links Ashkenazi Jews living today to this historical figure within the last 3,000 to 4,000 years. So he founded this company, primarily driven by personal curiosity. It was very much a cottage industry. Literally, a few hundred people would hear about this and decide to get themselves tested every year. And then we went live with Geographic in 2005. And the numbers started to tick up significantly. 23 and Me and Navigenics launched in 2007, in part off of the back of our success showing that there was a viable business there. But they launched with products that were priced at $1,000 and $2,500. So not a lot of people buying those. They dropped the price in 2008, 2009. And you see this uptick here. We continue up until 2013. End of 2012 beginning of 2013. The millionth person purchases a test kit. So it took us 11 years to go from zero to a million. The second millionth person bought a kit a year later. And we're over four million now, or will be by the end of this year. No signs of it asymptoting. And this is a really, really interesting curve from a business point of view. So there are lots of companies that have piled into this space. My buddy Ken Shaheen at Ancestry tells me that they're probably going to sell between 500,000 and 700,000 kits next year alone. So why is this happening now? Or in the last couple of years. Well, there are a few reasons. I think DNA has become part of the national consciousness. Big corporations talk about whatever it is being in their DNA. People are less afraid of Jurassic Park scenarios, because they know that it's very unlikely. They're less concerned about being cloned. All of these were major issues in 2005 when we launched. People are also more comfortable now sharing their most private information. When we launched in 2005, there was no Twitter. There was no Facebook. And people dump stuff out onto the internet for public consumption now that a generation ago, people would have been appalled at. And now it's standard. And I think part of that is trusting companies with their genetic information. And I think this is a really important part of it. We've hit enough people having tested themselves now that it's very likely when you go to a cocktail party with 30 or 40 people in the room, at least one or two of them will have tested their DNA. And they may be talking about it. And so we've reached this threshold for viral spread. Word of mouth, so important. A great parallel would be the film industry. This is what the film industry typically wants to see. You pump a ton of money upfront before the film comes out into promotion, marketing, advertising. And you make all your money in the first weekend, or the first couple of weeks. So ideally, you're going to see in the film industry something like that in terms of revenue. But occasionally, a film will come out. And it's released in a few theaters. And it generates some buzz and starts to get good reviews. And the filmmakers and the distributors say, well, maybe we should release it in more theatres, and so on. And it continues to grow. And I think that's what we're seeing in the genomics industry. My Big Fat Greek Wedding being one of my favorite films, a really good example. And you'll notice that it actually made more money in the end than Twilight did. So anyway, I'm going to end there. And if you want more information about the Genographic project, there's the url. Thank you. [APPLAUSE] -OK. So what we'll do now is have a little discussion among ourselves for a few minutes as people collect their thoughts in the audience. And I'll ask when we transition to the audience in a few minutes that you stand in front of the mic, and that will be my signal to make that transition. And put your comments in the form of a question. Just like Jeopardy. A short question, ideally. And we'll ask you to identify yourself, as well. So I'll start this off by asking John a question. So you had a tree that included Neanderthals and Denisovans and modern. And the Neanderthal had all this flat, non-diverse branching. But the Denisovan had just one branch. But you described all kinds of modern DNA. Is there a difficulty there in characterizing the diversity? Tell us about that. Sure. The Denisovan we only know about from one genome, fundamentally. We have a couple of other specimens that have mitochondrial genomes that we know that it's not just a one-off. But we only a very limited amount about its diversity. We have two ways of looking at diversity with genomes in this sense. We could look at between the samples, in a sense. And we can look at within samples, because a genome encompasses variation from the entire population that produced it, in a sense. With Denisovans, we have an additional option, which is to look at the present-day people that carry some fraction of Denisovan genes, and characterize the diversity between that fraction in living people and that same fraction in the ancient genome. Sort of interesting with Denisovans, because when you do that, the Denisovans-- I love the fact that we have a name for something that we can't see. But the Denisovans that contributed to living people are different from the Denisovan that we have in this cave. That may be not too terribly unexpected, considering that the living people that carry it are in Australia and in the Sahul ancient land mass, and the cave where we find them is in the Altai. But this may have been a population that, itself, was diverse, maybe as diverse as living peoples' populations. Yeah, there's always a problem comparing variation that way. But we can try to parse it out. And you look within those genomes, and you're looking at what are homogeneous ancestral populations of them. And where we see divisions between them, they really stick out to us. With living people, you're looking at-- I like to emphasize to people-- you're looking at a population structure where it's actually very difficult to create a tree like that, because it creates the impression that people are quite separate, when in reality, every different component of our genome has different geographic distributions. In fact, we're sort of a smear. In the distant past, it looks like we were less of a smear. It looks like we really were, in some sense, subspecies once upon a time. And today's humans are not. Today's humans are really clinal in their variation, and are exceptionally similar compared to these ancient people. -So just to follow a tiny bit more. If you did that same exercise of comparing modern Denisovans with ancient Denisovans, and it looks diverse. And the Neanderthals, your whole tree was ancient. What if you look at modern Neanderthals, like you and me? And are we non-diverse, as well? -It's a super question, because it's the obvious one. And people haven't done it yet. We are looking at, in you and me, 3% of our genome coming from Neanderthals. And that 3% in you and that 3% in me doesn't overlap a whole lot. They're fundamentally rare genes. And we are mostly not overlapping. -So that means there is 6% between the two of us, right? -We don't know what the asymptote is. But if you start adding up people, you start to get up to-- we, today, sample, among probably everyone in this room, more than half of the Neanderthal genome. But it's distributed as rare segments in different ones of us. -So somebody might have all of it, huh? -If they do, I want to write a comic book about them. -They'll be my superhero. So quick one for Beth. By the way, any of you can chime in here. You are making the argument that as the habitat degraded or disappeared or went up, the populations would track for your stuffed animals, the horse and the caribou and so on. But for the caribou, it looked like the population is almost perfectly flat, while the habitat was going really south fast. So did I misinterpret that plot? -No, it's right. Caribou was non-significant as far as tracking the habitat changes. And caribou, they've lived in the very high Arctic, and they need this. They have a very good strategy for surviving long-term. And that is that they hang out in places where people don't. So they still live in the very high Arctic. They eat lichens and things like this. And their populations have actually done really well, as other things that would have been competing with them for resources have collapsed. So what you see there is a second-order effect of the horses and bison and mammoths disappearing from the part of the range that they would have overlapped with caribou. And even though the habitat is declining, caribou have hung on. Something about their ecology makes them different. And because there's no longer any competition, their populations have actually increased in size, even though the amount of habitat available to them is declining. This is just further proof-- like we needed any-- that things don't act in isolation. Species and organisms are part of an ecosystem. And the ecosystem is dynamic and always changing. And what we observe in these different species is a combination of effects from everything that's going on in that ecosystem. -Spencer, you concluded on a very provocative note. I thought it was really interesting. Your plot is going up quite steeply. When do we get-- so we're like 2 million now. When do we get to 7.2 billion? -When the price drops. -That's meant seriously. -I don't think it's going to anytime soon. I think there are huge markets outside of the US. Most of the sales at the moment are in the US or Canada. I think what's going to drive that is utility. And the primary utility people gain from the testing right now is genealogical. So they're finding second and third cousins in the database. As the database increases in size, you increase that utility. You're more likely to have cousins that are in there. So it's price and utility. Sequencing is becoming very, very cheap. And I'm on the scientific advisory board of a startup called Helix, which is a spin-off of Illumina. And one of the things that's underpinning what they're doing is an exome-- so all the coding regions of your genome-- for significantly less than $100. And that is simply unattainable outside of that organization right now. And as that price approaches zero, it's going to become much more widespread. -So once we have a family tree of everybody, we've had instances where people have been convicted or found based on getting DNA from their brother or sister or something like that. So basically, it will be nowhere to hide. -In essence, yeah. Yeah, that's what it means. I think, again, showing utility is going to be important. But I do think that in the next 10 years, it will be routine to have your child tested either at birth or in utero with non-invasive prenatal testing. And you will be seen as an unfit parent if you choose to ignore that information and not get yourself tested. And in fact, there was a lawsuit a few years ago in France. A child born with Down syndrome sued his parents successfully for having had him, knowing that he was going to have Down Syndrome. Now, there was a technical reason he did that. It was so he could access certain financial benefits as a result of the ruling. But you have a couple more lawsuits like that, and there's going to be a strong incentive for people to do this testing. -Wow. That's impressive. Beth, I noticed on your horse slides you had GRIN2B as one of the genes on their behavior. Sorry. This has-- -Pass. -This has been associated with actual experiments have been done on mice showing an impact on their intelligence. -Does it make them smarter or not? -Depending on what you do with it. -Depends on the mutation. So I wonder if the horses have the smart version or the dumber version? -Just wondering whether you have done anything. -I think I have the dumber version. -You had it under behavior. What did that mean? -I don't know. Those were lists that came out of my paper. I'm sorry. Pass. -Have you been to Sergei's Pleistocene Park? It's not that far from the Yukon. It's right next door, according to your favorite politician. -I haven't been. Have you? -I haven't been there, either. -Do you want to go? -Yeah, sure. -Let's go. -Let's do it. OK. -This is a field trip. -A National Geographic trip, right. -Do you have that power any more? -I do, actually. I'm still leading jet trips. -There might be enough people in the audience who could underwrite it for us. -Who is interested? -Who wants to come too? Do you know what the square kilometers is? -He's always buying more space. He just bought another big plot of land just south of Moscow and some farmland that he bought up. He's calling it Pleistocene Park 2. -It's a little further south. -Yeah. But it's closer. -To a population center, yeah. -It's easier to access by a highway, so that he can get more visitors. -This is a real real estate opportunity for all of you out there. We're going to need a lot of land for the 80,000 mammoths we're going to have in a few years. 80,000? -Well, the bison made this huge resurgence from just a couple hundred bison. Basically extinct to 500,000 now. And, of course, there has to be ranchers or public lands to support all these bison. And the reason it did-- I'm sure everybody can guess-- is there are some financial incentives. And it was the bison burgers and other meat that's about 10 times lower in fat and cholesterol. -So you think mammoth burgers are going to be the-- -Well, we'll make low-cholesterol mammoths. Yes. -The question is, so when we think of the past in prehistoric creatures, whether they be people or mammoths or other things that used to walk, so much of, I think, our understanding of them is through the hard tissue remains that we have of them. So the experience of going into a museum and seeing a mounted skeleton, or thinking about physically what they appeared like. How much do you think the further progression of ancient genetic technologies are going to allow us to conceive of the soft tissue and the physiological processes that made them different, as opposed to simply the fact that they look different. -Please state your name. -Adam [INAUDIBLE]. -Well, from the human perspective, I would say we're talking about things like Neanderthal immunity and Denisovan altitude and metabolism. And that the genes that we have today from Neanderthals in northern Europeans seem to be associated with lipid metabolism. It's stuff that you never would have seen in the archaeological fossil record. And that's really exciting. But the other side of that excitement is that our inability-- when we see this gene is there, what does it do? Our inability to understand that is not based on our lack of fossil evidence anymore. It's based on what we don't know about human biology. And so what for me the promise of this is that by studying the evolution of these things, we actually get a different avenue on understanding their biological significance. So it's actually not just about figuring out what the Neanderthals were like. It's about using the fact that Neanderthals have an evolutionary history and a relationship to us to figure out how our bodies work. And that's pretty cool. -Do you think that the majority of Neanderthal DNA that stuck around in the human genome has been selected for? -I think that the majority is neutral. I think the majority is just, here it is. It's a marker of interactions. And we know that there are windows where nobody today has the Neanderthal version. So we know that there are gaps that represent things that they had that didn't work. There are some things that look like they're useful, that they've really grown in frequency beyond what you'd expect. -MHC alleles. -Exactly. -I think this question actually brings up something that's important, both to the work that you're doing with mammoths and to a lot of work that we're doing with other animals. And that is that we now have more letters, more A's, G's, C's, and T's than we understand. And for humans, it's a special case. We know a lot more about human biology than we do about elephant biology or bison biology or horse biology. So we have the capacity to make these lists of genes that were identified, mostly in models-- model organisms, not wild animals-- and guess what they might have done. But we're very much at the point right now of trying to figure it all out. We have a lot of massive phone books filled with numbers, but no names associated with those numbers. -Which is a huge shift in genetics. When I was getting my PhD in Dick Lewontin's lab, Lewontin was famous for saying, we've created this huge apparatus in terms of theoretical population genetics. And we're ready to crank the handle on the machine and get it analyzing data. Where is the data? Generating the data was the hard part back in the '80s. And now, it's just ubiquitous. -This has been a really wonderful morning. Thank you, all of you. My name is Abigail. I run a nanotechnology lab at the Koch Institute at MIT. And this question is to all four of you, but John in particular. You mentioned at the beginning of your talk that 10, 15 years ago, there were really big questions that divided the communities that have really now had a chance to come together, which is an amazing thing. What kinds of questions do you see now as being really divisive that DNA has yet to be able to answer? Maybe it could in the future. But what are some of those big, dividing questions? And this could be to everyone. -I'll take it first, because the other part of talk that I gave in Gibraltar was this side-- what does the future look like? And from my point of view, I'm interested in things like how did it come to be that humans had this population structure in the past? What does that mean relative to the way that we understand humans to be distributed today as a widespread species with great genetic commonalities among us? What can we make of rare evidence in the past? I think of archaeological evidence, and the fact that we're now discovering that there's significant plant use by Neanderthals. For instance, we used to think of them as purely meat eaters, but we're finding the evidence of the plant foods that they ate in dental calculus. And now, we're able to actually do some sequencing of oral bacteria to try to understand their oral microbiomes. And those sorts of things which suddenly give us a window on something that we couldn't look at before, but the window is small, and we know that it represents a larger world. How do we use rare evidence to talk about things that were probably important, but we can't see very much of? I don't know that we're now polarized. I get a lot of happy feelings. I don't think that we're divided by things. But I think that we're in a phase where we haven't thought of the questions that will dominate what we're doing for the next 15 years. -Heather [INAUDIBLE]. I'm interested in human evolution, particularly the evolution of language. And I think that that may be significantly tied to the difference between humans and non-human primates being concealed ovulation. The question that I'm curious about, has anyone identified where on the genome the genes for concealed ovulation might be located? Could that be figured out by comparing it to non-human primates who do not have concealed ovulation? And once you have identified the genes associated with concealed ovulation, I'm wildly curious to know if the fossil records, if any of these ancient fossils-- I think if we can find an indication that they had concealed ovulation, then I'm really willing to speculate that they might have language skills for a whole lot of other reasons. But I'm just wondering if anybody's thought about that, and if that could be identified, and what the significance of it might be. -That's a good question. --[INAUDIBLE], presumably, is looking into stuff like that. -Yeah. There are a number of people looking into these sorts of things. A significant problem. This falls into the category of we don't really understand how it works in humans. And comparisons with other primates where it's not concealed ovulation are a window of looking at that. But also, experimental models become a possibility. And people make transgenic mice and try to figure out what's going on. But at the moment, we don't know the answer. -Good morning. I'm [INAUDIBLE]. I'm researcher at UMass Boston. I have a question about a very widespread kind of notion. While both John and Spencer pointed out that notion again, it is that I want to see how truthful the fact that we all originated from Africa. How about ancient people in the Middle East? I'm Originally from Iraq, Babylonian Assyria. And I have my own family tree over there. And it goes back to, let's say, just before Islam. And that's all. There's known lineage. We cannot be sure about that. So I want to know why is that? How far is that? How truthful that kind of notion? On what basis scientists based their notion that we all share African genes originally? -It's based on the fact that Africans have far more genetic diversity than people living outside of Africa. It's just absolutely clear. If I could show you a tree of what the mitochondrial lineages really look like, 98% of the variation is found in African populations. The non-Africans are a tiny subset. Now, we've given them more letters, because scientists started off looking at Native Americans and Europeans. And so they just added new letters. So everybody in Africa falls into what they call the L branch. But L is huge, and very, very diverse. This is mitochondrial DNA. Same thing for nuclear DNA. You see far more diversity within Africa than outside that. And the only way to explain that is that people have been living in Africa for longer, accumulating more diversity. It's had a larger effective population size. It hasn't gone through the sequential bottlenecks that you see in non-African populations as they move into the Middle East, then East Asia, then the Americas, and so on. It's just it's very clear from the genetic information. -Yeah. We do have ancestry from some non-African peoples. But the fraction is quite small from Neanderthals and other people. One thing to keep in mind is that the time scale that we're talking about for the colonization of the world, initially, by these African people is on the time scale of 50,000 to 70,000 years or longer, which, in historic terms, of course, is 10 times the length of all recorded history. So we are talking about events that are shaded in the past. But they were events that fundamentally shaped what today's genetic variation throughout the world is. -Now, there are some paleoanthropologists who feel that Homo erectus originated in Asia and migrated back into Africa, and ultimately that's the source of modern humans. In a long circuitous way, ultimately, erectus does come out of Africa as well. But they went out into Asia, and possibly came back, and then went back out. It's very complicated. -The earliest good erectus stuff we have is outside of Africa. -Dmanisi. -Yeah, Dmanisi. So it's quite possible that there were multiple foci that led to, ultimately, the success and proliferation of what is today a fundamentally African origin population. -Leonard Katz, MIT. There's been debate about what role lethal raiding between groups may have played in human evolution. Besides some evidence from hunter gatherer groups, there's that of chimpanzees, which practice lethal intergroup raiding, which can lead to local extinctions of groups. On the other hand, there were the bonobos, which seem to be nicer. In something that NPR ran this summer, they seem to be suggesting that that interbreeding shows that our ancestors were like bonobos. On the other hand, there is genetic data that seem to show differences between mitochondrial DNA and Y chromosome DNA in populations, which may show selective wiping out of local males by conquering males. Now, how do you see the data that you know, which is much greater, connecting with this debate? -This is one of the big shifts in our understanding. Archaeology has been through a very interesting history over the last century. So a century ago, it was a question of looking for homelands and the wandering of peoples, and as they spread, they spread their culture. And there was a lot of talk of conquest and so on. And that fell out of favor in the middle of the 20th century. What seems pretty clear there, though, from the genetic data, is that that's probably the way things happened. So as part of the Genographic project we had an ancient DNA team led by Alan Cooper and Wolfgang Haak. And they, as part of their contribution to the project, did these things they call transects through time. Very well-studied archaeological sites-- Central Germany, there is one in Spain, there's one in northeastern Europe as well-- where they go back to about 6,000 years of history. It's well-documented. We have carbon dates. We know exactly what the cultures are. When you see a cultural shift at a certain point in time, you see an abrupt genetic shift, as well. So maybe the people wandered away and another group came in. But I think what's more likely is that you literally had conquering groups of people who came in and killed them off. Like it or not. My name is Irwin Shapiro. And I'm an astrophysicist by profession. I have an interest in biology, just as an avocation, if you will. I have a question in regard to the DNA. I hear statements like 99.6% of the DNA of humans is the same as chimpanzees or whatever. And I also hear that we only know what something like few percent of our DNA is good for-- making proteins. There are 23,000 genes, or whatever they are. I was wondering if the differences between individuals in a given species and between species, whether anyone has looked at the percent differences in the stuff we know what it does versus the stuff we don't know what it does, and whether this could give us any insights into possible testing with lower animals or whatever as to what the stuff we don't know about might be good for? If that's a coherent question. Protein-coding genes-- the things that we know, at least, that make a protein-- tend to be conserved, which means that they don't vary as much as other genetic parts of our genome, because if they change, it often breaks it. Conserved means that different species are more similar than they are for the rest of the genome. So in that sense, the parts that we think we know that, at least, they make a product, and here's what it is, tend to be less variable. But, of course, the variations that occur in those parts tend to be pretty significant, because they are variations that change the function. In part, we use evidence about how much different parts of the genome vary to try to understand how that evolution happened. And that's true not only, of course, within humans and other primates, but across huge swaths of species. -I'm Catherine [INAUDIBLE]. I work with students at Regis College. And I wanted to ask a question related to probabilities. In other words, when we say there's been a genetic change discovered here, and we see that same change here, we assume there's relationship. But what's the mathematical probability that these two changes happened independently? -So there are regions of the genome that change very rapidly. They're hyper-variable. Microsatellites would be an example of that. So repeats of, say, 10 or 12 or 14 CAG CAG CAG. And they tend to add and subtract repeats very, very rapidly in an evolutionary sense. So in that case, you do have convergence. We do have homoplasy, as it's known phylogenetically. But for the typical point mutation, unless you happen to be in a region that's prone to a high mutation rate, it's exceedingly rare that you're going to see exactly the same mutation in the same location. Just do the math. You've got 3 billion some-odd nucleotides in the human genome. Depending on the population size, yes, if the human population size were infinite, you would see the same mutations occurring independently. But the human population size has actually been relatively small throughout most of our history. And we went through a near-extinction event, probably around 70,000 to 75,000 years ago, where we think the total number of humans alive dropped down to fewer than 10,000. Possibly as few as a couple of thousand. We came back from that. And that's why we have a remarkably low level of genetic variation as a species. So it really depends on the region of the genome you're looking at. The ones that we tend to use to reconstruct these trees don't change that often. And because of the tree structure and the context and the fact that they're not recombining, and so you're dealing with a single intact chunk of DNA for the Y chromosome and mitochondrial DNA, when you do see recurrent mutations, you can actually notice them. They stand out very clearly. And you can exclude that as a marker. -In fact, we use the rates of the genome that mutate really quickly, that change a lot, when we're interested in learning something that happened recently in time, and the regions of the genome that are more conserved when we want to understand deeper evolutionary history. So if we're trying to reconstruct the relationship between all great ape species, we're going to focus on parts of the genome that mutate more slowly than if we were going to focus on reconstructing the population history of the bison from Wood Buffalo National Park. We might use something that's really fast-changing. And there, you really do have to incorporate the possibility that you see the same mutation happening more than once in your models. And that's done probabilistically. -We're getting close to the last two questions, I think. -My name is Charlotte Seed. And I manage a genetic biorepository at Northeastern University. And my question is primarily for Beth. In the field of ancient DNA, what are considered the best practices for preserving these incredibly precious samples? Do you, say, treat them any different from the other samples in your lab? And has your work with these DNA samples changed, maybe, your approach to archiving and storing current DNA? -Yes. So the biggest problem with ancient DNA is contaminating the sample that you already have. So we have a separate lab that everybody wears the bunny suit in. It looks like a lab that you might work in if you're working with really terrible diseases. But rather than having negative air pressure, we have positive air pressure to push stuff out of the labs that we don't want to get in. Everybody covers up. And we never do any sort of amplification of DNA in the ancient DNA lab. And there's only one-directional workflow. There's all sorts of things that we implement. Sterilize everything that we're using. Try to eliminate DNA. And it's still there. If you do deep sequencing of nothing, you will get all sorts of domestic animals and human DNA. It just happens. And microbial DNA, obviously. We do know that short-term storage affects the preservation of DNA. In 2000, long time ago, we were using PCR just to amplify different length fragments from different samples. In the '50s, there was gold mining taking place in Fairbanks, Alaska. And the samples that were discovered, the bones that were discovered as part of this, were split up. And some of them stayed in Alaska and some of them went to the American Museum of Natural History in New York, where they stored them in the attic. And in Alaska at the museum, there was a constant temperature. Little bit colder than room temperature room where they were stored. So we took samples that were the same age-- about 20,000 years old-- and amplified them. They were all taken out of the ground in Fairbanks in the '50s. And the samples that were in New York, the average fragment length that we could get out of them was about 70 or 80 base pairs. But we could get 600 to 700 base pair fragments out of the Alaskan ones. In 50 years of being in the attic, where in the summer it was 40 degrees above 0, in the winter it was 40 degrees below 0 Celsius, this had broken all of these fragments of DNA down in just that short of an amount of time. So the preservation of samples after they have been taken out of the ground is, actually, critically important for preserving their DNA. And yeah, we try to keep things in cool and constant temperature environments, with as little exposure to changes in ambient moisture as possible. I think the water, actually, expansion and contraction of water molecules, may physically break down the DNA. But yeah, it has changed the way we think about things. Hi. My name is Beth Thomas. I'm with Harvard management. And I have a question for Spencer. And it has to do with the future utility of the data that you may be collecting, or they are collecting in the genographics project that you're doing. And it's been interesting watching Facebook. Just in a few years, they're well over a billion members, albeit it's free. But as the pricing for these kits declines, and maybe more momentum and just the word of mouth gets out, it's going to be interesting to see just how many people do use those kits. And I'm just curious what you think the maybe future of that data is? If there's been a progressive reveal or progressive realization about what might be what the information from Facebook might be used for it in the future-- ads, whatever-- is there a similar trajectory with the data at that project? -So, again, what's driving a lot of the interest in consumer genomics right now is genealogy and ancestry. Some people literally know nothing about their ancestry. They're just curious to see, am I part European, part East Asian, whatever it might be? Other people-- African Americans-- are looking for a connection to a tribal group, perhaps, in West Africa, because they've lost that written history about that side of their family. A lot of people are interested in finding their cousins. They've got some issue in their genealogy that can't be solved with written records. And the only way to resolve it is to test disparate parts of the family tree and see if they actually do connect. So ancestry is the primary driver right now. That's for a couple of reasons. One is that the FDA shut down that aspect of 23 and Me, which is one of the big players in the field, the medical side. Part of the reason for doing that is because of the way 23 and Me chose to deal with the FDA. I don't think if they had handled things differently they would have necessarily had that part shut down. Part of it, though, is because we haven't really shown the utility of medical genetic testing for most healthy people. We still don't know enough about the underlying biology and what all of these millions of SNPs-- single nucleotide polymorphisms-- really do. Do they have any effect? Is the effect significant? Is it actionable? If somebody tells you you've got a 1.2% higher risk of type 2 diabetes because you've got a marker at whatever the locus is, is that really meaningful to you? Those are the bigger questions in human biology. I'm going to have to take strong exception to both of those. When the FDA shut down 23 and Me, it did not shut down 500 other medical genetics centers. And they were providing very high-quality data at many stages of the human cycle. So there are very valuable things that you can do pre-conception, while you're still deciding who you're going to mate with. Noninvasive prenatal testing you can now get from mother's blood. -Absolutely. -This is done in millions of women around the world. -But I said the utility for healthy adults hasn't really-- -But you still have the market includes healthy adults that are planning on procreating. And then, for healthy adults, there is a long list of things we cannot do. But there is also a significant list of things we can do, including various cancers. Angelina Jolie was the-- -BRCA. ---the person who really changed consciousness a little bit on that. So I think there's been a tendency in the media to focus on the half empty part of the glass. But I think we've reached the tipping point that Helix and others will exploit and make it available to all of us. So it's not 20 years away and always will be. It's happened a few years ago. -Oh, I totally agree. -It became valuable for adults whether or not they're procreating. -Absolutely. The problem with the 23 and Me data, of course, is that it's all based on chip results. The markers on chips are relatively high frequency. -They're at a relative minority of the medical record. -And we're not discovering anything new. The real utility is going to come from sequencing a lot of people, as you know. -And that's exactly what the 500 others do. All the high-quality medical data comes from them. And some of them are in the $100 to $200 range. -I want to thank this panel. This has been fascinating.
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Channel: Harvard University
Views: 371,292
Rating: 4.359477 out of 5
Keywords: DNA (Chemical Compound), Radcliffe Institute For Advanced Study (College/University), Harvard University (College/University), Neanderthal (Animal), ancestor
Id: pOj170kogg0
Channel Id: undefined
Length: 143min 20sec (8600 seconds)
Published: Thu Oct 22 2015
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