well we certainly have a terrific turnout this afternoon I think the reason for it was because you all heard rumors that a Neanderthal Institute director was going to introduce the speaker I am that neanderthal Institute director Eric Green director of the National Human Genome Research Institute I want to welcome you to actually a special talk that the Institute is putting on and shortly you'll be hearing from our special guest doctors sponte pay bow doctor payable received his PhD from the University of Upsala in Sweden and he conducted his postdoctoral research at the Institute for molecular biology at the University of Zurich in Switzerland and also in the department of biochemistry at the University of California at Berkeley now if you fast forward he is now the director of the Max Planck Institute for evolutionary anthropology in Germany he's also an honorary professor of genetics and evolutionary biology at the University of Leipzig in Germany and a guest professor of comparative genomics at the University of Upsala in in Sweden and previously he was full professor of general biology at the University of Munich now dr. pabo is truly an authority on the study of ancient DNA he was the first to successfully clone DNA from a mummy his DNA sequencing efforts have determined that ancient bones come from a previously unknown species of hominid called Denisovans which he's going to talk about in a 2009 he completed the sequencing of the neanderthal genome in an effort that included a collaboration with dr. Jim Mullikin the director of the NIH intramural sequencing center at NHGRI and recently his research has shown that Neanderthals interbred with modern humans some 50 to 80 thousand years ago this year dr. Paiva had a book come out entitled Neanderthal man in search of lost genome and in this book he explores the concept of what we can learn from the genes of our closest evolutionary relatives it details his impressive portfolio of genomics research from the early 1980s to the present day and also though also vote notably explores the origins of modern humans and our relationships with Neanderthals in February his book received a glowing review from the journal Nature in addition to his book he's co-authored over 200 publications and his list of international awards and accolades as impressive as an example 2007 he was named by Time magazine the list of 100 most influential people in the world and various other Awards of decorate his very impressive CV he was also recently elected to a member of the Royal Swedish Academy of Sciences and he was also a Gruber Prize winner in genetics it's been just a pleasure to have a Slainte here this week he actually two nights ago down at the Smithsonian's National Museum of Natural History gave a public presentation put on by the Smithsonian associates involving a partnership between NHGRI and the Smithsonian Institution associated with our exhibition genome unlocking life's code and associated that are a series of evening public events and Sante was featured two nights ago as one of those events and it was really terrific and he's even been more generous with his time he spent yesterday at the Smithsonian giving a couple of talks talking to their scientists and then he's spending all day today here visiting NIH giving this talk and visiting with NIH scientists and then back tomorrow to the Smithsonian for more meetings before he gets to fly home to be with his children this weekend so it's truly a pleasure to have Svante here joining us at NIH today so please join me in welcoming a gifted scientist a valued colleague and a good friend dr. Sante thank you very much it's really a great great pleasure to be here I think it's 25 years ago when I was last visiting physically then I aged although we have collaborated a lot and it's impressive the changes and growth that has been although it's much harder to get into the facilities now than it was 25 years ago so what I wanted to do then is talk a little bit about the technical efforts in retrieving ancient DNA and sequencing ancient genomes and then focus on what we have learned by studying genomes from our very closest extinct relatives now under tolls and relatives of Neanderthals and for the last third of the time or so talk about where we go from here how we can use these genomes to try to get to functional differences between us and other organized articular than Neanderthals but just as a means of introduction I want to remind you the about the fact that most of you are very well aware of that if you look at genetic variation among present-day people you find most of that variation in Africa whereas although there are many many more people living outside Africa you actually have less variation there and not only that there is a almost all more common haplotypes anyway that you find outside Africa have closely related sequences inside Africa but there's a component of the variation so to say in Africa that you don't find outside Africa and the interpretation of this is that modern humans evolved in Africa accumulated variation there and a part of that variation went out and colonize the rest of the world and by different tricks looking at linkage disequilibrium for example in these haplotypes outside here relative to inside you can estimate when that exodus out of africa happened and it's in the order of 100 thousand years ago or less so this is a basis of the recent African origin model for the emergence of modern humans but there is if you like a problem with this model and that is that 100,000 years ago there were many other forms of humans around most famously than Neanderthals in Europe and in Asia other less well described force of humans so here is a reconstructed skeleton of a Neanderthal compared to present-day human the Neanderthals were the sort of robust forms of hominids they appear in the fossil record three four hundred thousand years ago and disappear again around 30,000 years ago generally rather contemporaneously with that modern humans appear in an area so there are two major ideas around in paleontology of how modern humans relate to nonlethals and other extinct force when they come out of africa one in this toe total replacement model says modern humans comes out replaces these other forms with no mixing whatsoever another idea is that these modern humors had come replaced down the halls but also mix with them and accumulate genetic variation from them to present a people in Europe and with other forms and in Asia to present a Asians so the first so you could regard this a sort of a sliding scale from total replacement seer a percent contribution from these extinct forms of humans to more and more contribution up to total continuity that I think no one sort of advocates at least in 15 years or so so the first chance to test this with genetic means then came in the mid-90s when we got access to this specimen which is not just any Neanderthal it's the Neanderthal from the Neanderthal that was found in 1856 and gave its name to this group of hominids and was actually the first time I realized that there had been other forms of humans here before the present form of humans so we then extract DNA from such specimens under sort of cleanroom con to avoid contamination from from ourselves into the experiments and at that time with the technology that was there were PCR is focused on a particular valuable part of the mitochondrial genome cameras only amplifying it cloning pieces believing the substitutions that were consistently there and if you then reconstruct a phylogenetic tree for this mitochondrial genome you will find that all present-day mitochondrial genomes go back to common ancestor hundred two hundred thousand years ago and much further back half a million years ago or more is recommen ancestor shared also in the Neanderthal mitochondrial so since then we another sequence when the other mitochondrial genomes from Neanderthals they all fall outside the validation variation of present-day humans so it's quite clear from this there is no people walking around on the planet today whether mitochondrial genome from the unlit halls so in this scheme of things for the mitochondrial genomes total replacement lukas learned something else from this - and that was this age of around half a million years for the split of the mitochondrial genome of Neanderthals from present-day humans that suggests that the population split between what they came down the tall's and modern humans later happen sometimes after half a million years ago so that of course already means that the Neanderthals cannot be very different from us because if I ask compared to two pieces of DNA into Geno's today the average time back to common ancestor from those two pieces is somewhere around half a million years with a large barriers around the cross there is no problem to find some pieces in the genome where I am someone in order differ by a million years so that means that also if there was no mixture whatsoever for the nuclear genome it would be the case that for many parts of the genome someone today would be closer to nail the tall than someone else in the audience would be and if you move to another part of the genome situation will be different but this end it doesn't mean that the nandaka genome would be uninteresting to start it because they will look was still be part of the genome we're all modern humans would have fall outside the variation on the are metals and the opportunity to go after the neanderthal genome then came with high throughput DNA sequencing where you could leave this sort of trying to retrieve a particular piece of DNA but simply go and extract all the DNA you have in a fossil process it a sequence at all to exhaustion create a little data bank and start seeing what pieces of DNA here look human-like so there might be from the Neanderthal what is bacterial and so on so this worked for the first time in a cave site in southern Europe in the cave in Croatia this bone that is 38,000 years old and the first thing you will see if you look at sequences from such a bone is that they are indeed short pieces of DNA year 50 60 base pair starting anything approaching 200 base pairs also the it's only tiny fret of fraction of the DNA that actually cancelled an undercoat the vast majority in most cases 99% or more of the DNA comes from soil bacteria and fungi that have lived in a bone when it was deposited in the cave so we started a project and were very happy to get funding for an effort and to sequence entire a first sort of overview version of the Neanderthal genome and during that time we worked a lot on making the effort methods more efficient in how we come from a bone to a sequencing library that we can put into the sequencing machines the machines in that time got more efficient in terms of how many molecules it could sequence we look through many many sites many bones to find the ones with the most Neanderthal DNA in and was in the end three bones from that site in Croatia from three different day little individuals that generated data for the first version of the Neanderthal genome so we sequence a bit over a billion DNA fragments sort of mapped them to the human genome having algorithm to take into account that there are typical types of errors in these sequences that you have to take sort of into consideration and we have one full coverage of the genome so that we had seen just a little over half of the genome once but that gave us the first chance to start asking questions and the first question that we were interested in was this what happened when modern humans came out of Africa and met Neanderthals did they mix or not so to address that we did that in several different ways because this is very controversial question were really sort of wars and paleontology going on about this so I had a feeling we had to get it really right but one very direct approach to ask that was to say that if there was a contribution from the under toaster people in Europe we would expect people in Europe to share more alleles with a Neanderthal than people in Africa where there never been the albatross so it's this idea here if there is no mixture whatsoever the nom de taüll is equally far from people in Africa in Europe today whereas here it would on average be closer to Europeans we went out at the time and sequenced five genomes we would have exactly the same error rates etc one person from Europe for us of course the archetypical European is a French person so this is a French you know to African genomes one from China one from Papua New Guinea and we did a very simple analysis we are saying if you compare now these two African genomes find positions with a different from each other and then we take the Neanderthal genome and say how often does this match one African or the other as his Neanderthals have never been in Africa there's no reason for a noun little to be closer to one African another it should be 50/50 which is the case statistically speaking however if we compare European to an African we found significantly more matching to the European individual than African imitative when we went to China versus Africa we again find the same thing and even Papua New Guinea we see the same thing so this was very surprising to us at the time because if we would see a contribution we would have expected it in Europe when the undertones had lived not in Papua New Guinea and China where they had not existed so the question was how could this be and the sort of model that with time suggested as a most plausible model that has since in borne out by much other work also from other groups is to say that when modern humans came out of Africa between fifty and a hundred thousand years ago they presumably passed by the middle east and we know the live noun that was there so those modern humans mix in the undertones and then became the ancestors of everybody outside Africa they would sort of carry with them this Neanderthal contribution out into the world to the extent that people outside Africa today have something between one and two percent of the you know from Neanderthals there has been we now know begin to know a little more about this admixture and process also because it has been observed that in East Asia others actually more Neanderthal DNA but 20% more so say instead of 1% one point two percent then there is in Europe and Josh a key published a paper in science in January where they model this contribution from Neanderthals once to the common ancestor menorah all Africans and later admixture went affecting only their ancestors of Asians and that fits the data significantly better so there seems to have been to events of admixture here one to everyone one perhaps in Central Asia or something like that that effect ancestors of Asians you may also ask when did this happen that was also important to exclude other scenarios and an approach to estimate that came primarily from David Rice lab in in Boston which takes advantage of this fact that if you have two populations they down the tall's and modern humans mixing the first generation hybrids will of course have one chromosome from Neanderthal one from the modern human if these hybrids then continue to live in the modern human population and mix with them you will have recommendation in each generation of course so this noun the tour DNA will be broken down to smaller and smaller pieces as generations go by so you can then use the size of such Neanderthal shanks to get an approximate age of when they enter the human gene pool so you're looking at things like this if you have European sequences up here variants are sort of indicated in yellow the Neanderthal down there you will find that some Europeans here are almost identical to the now and at all over some tens of thousands of base pairs and quite different from everyone else so you look at the size distribution of these things make some assumptions about mutation rate generation times and and and genetic recombination landscape and arrive at a date somewhere between 37 and 86 thousand years ago which fits with when modern humans came out of Africa now this relies on a lot of sort of assumptions this modelling and I will cause always a friend of real direct data there is no cause another way to go after when this happened and that would be to go back to really early modern humans and see if they had not mixed with Neanderthals or not and it's beginning to become possible to do that I think this is a place in Western Siberia called little town called ostium where two years ago one found a bowl on the riverbank here and this is this bone here that we have just recently analyzed so this is not published yet but we've sequences you know now 242 X coverage from this bowl and we've also carbon dated it and to our delight this bone turned out to be 45,000 years old so it's clearly the earliest modern human outside Africa and the Middle East that is known and we have a good genome of it now so if we now just look as an example here on one chromosome chromosome 12 and plot here what comes from Neanderthals in Europeans and Asian's you can almost see that there is slightly more Neanderthal contribution in Asia than in Europe actually when you look at this and the question is this now this 45,000 year old individual and that one mixed with Neanderthals or not and the answer is but indeed it has but we see a lot bigger chunks of course as we would expect back there so we can now go and look at sort of correlations with genetic distance impress the humans this is the data that leads to this date of 37 to 86 thousand years ago this is this forty five thousand year old early modern human and this leads to an estimate that it happened around 300 generation before this guy lived so that takes us to somewhere in the order 5060 thousand years ago so we're sort of beginning to narrow in on on the time point when this happened something else that were interested in is of course other extinct forms of humans than down the poles and we are very lucky to work together with professor derevyanko in Novosibirsk and his colleagues but if you professor shunko let excavate in many places in Siberia but particularly let this caves like there in southern Siberia then this cave on the border to China and Mongolia and Kazakhstan and Russia where the four countries meet so it's at this place here in the Altai mountains weather in 2008 found what they very skillfully recognized might be a bone from a human it's a fragment of the last phalanx of a pinky of a child so we sort of got this bowl and extracted DNA from it and it turned out he surprisingly well-preserved so where's our very best Neanderthal bones at four percent Neanderthal DNA this one had 70 percent endogenous DNA who went on and sequence the first sort of overview of this genome and to our surprise found that this Denisova finger has a common the genome as a common ancestor shared with Neanderthals but Neanderthal scenes have a long independent history so the divergence between this individual and the under course is substantially deeper than any divergence among present-day people here so we sort of then named this sort of group of extinct ominous donessa bells after the first site were delivered and found just as now in the Casa Gould Neanderthals after Neanderthal when they were first discovered it's the first time then that an extinct group of humans is described just from a genome sequence what we have happen sense is that we have improved our methods quite dramatically for retrieving small amounts of damage DNA there are many little tricks to this but the major trick is really a library preparation method where we use not double-stranded DNA that you add adapters to but start by the nature in the DNA by single strand ligation add on the adapters with the biotin on them so you can immobilize them synthesize other strand and then get something you can sequence so this means that each double-stranded molecule has two chances to enter the libraries of to say so whenever you have some chemical modification on one strand that makes it impossible to replicate or sequence a molecule the other strand still has a chance to enter the library and when we sequence deeply enough we actually see that you get those strands from molecules so we're now been able then we're then able to go and get high coverage genomes from these things so I have a 30x sequence from this finger bone here we will then have very good coverage of the part of the genome we can map short fragments to say 1.8 Giga bases or so of the genome so what you can then do is for example begin to look at a time back to common ancestry for particular parts of the Union you can look at the two alleles and see how far back they coalesce and you can do that for hundreds and thousands of parts of the genome and look at the distribution or times back through common ancestry and with a method that Hanley and Richard Durbin are developed you can then estimate effective population size back through time and obviously where you have more of these coalescence events is when the population have been smaller so in this example a dip here so from looking at a single individual you can estimate the population size history of the population that individual comes from so if you do this now for present-day people from Africa Europe and Asia you will see that everyone here shares or if this is a past everyone shares a decrease in population size an increase in population size and only quite recently since 50 hundred thousand years do we see a difference where Africans have a bigger effective size than non Africans and now we can look at this the nests of an individual and look on that population history looks and what you will then see is that if anything is slightly bigger here but then it sort of crashes down and goes extinct so it's quite fascinating to me that the population history of this individual is dramatically different than anybody else that's around on the today what you can also do when you have old but high-quality unions is to begin to look for what we could call missing mutations so an individual that died tens of thousands of years ago have had less time to accumulate mutations across so in this case if we say how many mutations do we miss here relative to the common ancestor to the chimp it's a little over 1% so if you now claim that this is 6.5 million years which is very uncertain but let's say that this would mean that this bone is 60 to 80 thousand years old and this bone is also small so you cannot carbon date it then you can actually not date it by any other means but when we haven't sort of there are many caveats with this such a day we of course have different error rates in this present the human genomes to actually see that apparent age of this present a you must vary by about 20% of this there's a black 0.2% variance here back to this but in the future when we are even more accurate sequences I think one can actually then date bones from genome sequences by this approach even bones that are on some types of smalls you cannot use other physical methods for dating you can ask for these decimals as the founders have they contributed to present-day humans and quite surprisingly they have done so but not very much in mainland Asia but out in the Pacific so Papua New Guinea Australians Fiji and so on so this suggests presumably that they were more widespread in the past so early modern humans mixed with them when they came to Southeast Asia are the ancestors of what is today the people in the Pacific so I think this is sort of an indication of what will happen much more in archaeology in the future from tiny little bones you can reconstruct a lot of the population history of individuals you find but very frustrating they have no idea how the skeleton of this individual what stone tools are made etc but to your summarize before we come to the last third of the talk about what we then think about the origin of Neanderthals and Denisovans first we think they have an origin in Africa and come out of Africa and evolve in western Eurasia to what we call Neanderthals and in Eastern Europe what we call Denisovans this is not to say that there were this widespread at any one point in time nor that it was the only forms of extinct humans there we don't really know where the border with down the tall's were but at some time in this Altai mountains a renowned atolls at some other time then it's then more than humans emerged in Africa come out of Africa a mix renowned it was presumably in the Middle East and around 50,000 years ago start spreading seriously over the world they mix once more when the undertones and for saps in Central Asia and they mix with the nestled somewhere in Southeast Asia and continue out into the Pacific and then these forms become extinct but they live on a little bit then so to say in people today in that something like up to maximum - in color fibers and perhaps of people still in account from the other halls and you add another 5% here from the distance in the Pacific now we sequence to extinct Eno's and found two cases of admixture I wouldn't be surprised if we find more for example in China in the future other forms that could also contribute it a bit no more if there would have been contribution in Africa I don't think there is necessarily an absolute difference between Africans and non-africans in that only non Africa's and this archaic contribution but so we have clearly rejected this total replacement idea we have a contribution from these extinct forms but the major picture is of course still an exodus out of Africa at most of our variation until Africa so sort of term for this I like to sort of suggest to something like leaky replacement or something like that there is a replacement but a bit of genetic contribution from these other forms so what's next then in this field well one thing that was actually are now just achieve a few weeks ago is that we now have a good name data genome also that we published directly two months ago quite curiously comes from the Altai mountains and the very same came as a Denisova finger were deeper down in the stratigraphy in 2010 they found a toe bone and that toe bone we obviously thought would be the myth seven we went on sequence the genome but it turned out to be far away from the donessa and close to other Neanderthals so this is a Neanderthal and we went on and sequence the genome to 50x so we can now look at that Dino - so if you just look at hetero zygosity for example how much variation is there between the two versions of the genome here if we compare present-day Africans to non-africans we see this at non-africans and less variation and here than the Denisovan and Neanderthal so they have very little variation extremely little and not only that if we look at this Neanderthal genome we found something else we found that there were huge chunks of the chromosomes that were identical between the two parents so an example here of chromosome 21 whereas we don't see such long pieces say in the Denisova genome this obviously indicates that the parents of this individuals were very closely related so you can then model the relationships that this individuals parents must have had it must have been one of these four relationships they were have sabzi or grandfather granddaughter or these other relationships that are complicated I can't even describe them but it's sort of quite sort of interesting that we can get to some of the social things that went on in that cave sort of 60,000 years ago in Siberia and it will be very interesting when we have hiked average genomes from other Neanderthals to see if this is a general pattern in the under tall or something special for this population we do see evidence of closely related ancestry also further back in the pedigree of this individual it's not just in the last generation so we then have these two good genomes here we have one the under tall lok aboriginal from the caucasus and the one from croatia so we can now begin to look at contributions not only to into present-day humans but between these extinct forms so if we do that here modern humans now a little stanislovas we see this contribution around the halls to non-africans and from the nests events to people in the pacific we're now also with the high-quality Denisova genome see a tiny contribution to mainland Asia the people in China have something like 0.2% the nestling contribution but we can also see that have been gene flow from the Siberian Neanderthals into the nest verse and quite interestingly we find a quite old component in the Denisova genome that we don't see in the now nettles that comes from something else something that diverged earlier from the modern human lineage between 1 and 4 million years ago so it's very tempting to suggest that this is Homo erectus in Asia or something like that that contributes to the miss events so it's very clear I think all these human groups have mixed with each other but generally its mixture of low magnitude we don't haven't yet found something where 30 40 percent I come from some other group what you can then also do now is start to look more careful in present-day human genomes in the thousand genomes data for example for contributions from the under tools so there were two papers that appeared in January in Nature and Science one from David Rice group where we were involved and one from your shakers group in Seattle where when I've looked sort of at the frequency of integration in the thousand genomes data from Neanderthal pieces and you will see that are some things that actually reach high frequencies in humans 7080 percent so if you first ask what are those things that have risen to high frequency what genes to be fine they're the only sort of functional group we consistently finds or carotenes in hair and skin so something like that seems to come over and influence the phenotype today perhaps already earlier it had been shown from a group of Stanford from Peter perhaps group that MHC alleles had come over from the undertones and from the initials and sometimes reached high frequencies presumably from selection perhaps from a pathogen so and in December there was a paper published in Nature from the Sigma consortium that David Altshuler is organizing where they found a new risk allele for type 2 diabetes in Mexican Native Americans a liquid transporter but the risk allele carries for amino acid differences from the non risk allele and this risk allele occurs in East Asia and sometimes up to 25% or so Native Americans and if you make a tree of the risk alleles and non risk alleles and put in the Neanderthals here you will find that the Neanderthals fall right into that so this is obviously an allele that had come over from Neanderthals into ancestors of Native Americans in Asia somewhere and recent to high frequency perhaps because it converts some advantage in starvation or something like that and now causes type 2 diabetes so some of this mixtures where these archaic forms actually have seems to have some phenotypic consequences what you can also look for here is of course regions where you don't find contributions from Neanderthals so you can look in present-day genomes where we put in is where you would statistically the undertow contribution yet you don't see it it seems to be negative selection there and these are some examples of that on the X chromosome and XO elsewhere and if we ask what genes are located in such deserts as we would like to call them on the underdog contribution where are those knees expressed the only tissue that stands out with genes expressed in such regions or genes expressed in the male um line and testicles it's very tempting to suggest that maybe the hybrids had some problem with male fertility which of course is not uncommon when close related populations mix with each other with that horse and donkey or what have you that the male offspring is sterile and the females are fertile so there may have been something like that going on but to end then I would like to spend a little bit of time on what I perhaps fine as the most exciting sort of future development of this and that if we can get to sort of things functional things that are unique to modern humans relative to our closest relatives the things that have changed here which we can now identify when we have the high quality in the under colander nestled in genomes that have changed here it spread to everybody today no matter where we live on the planet so things that happened here and became fixed in humans very recent in our history and why are those sort of changes particularly interesting what I do think that there are some things that have happened when modern humans came that a really set us off on a totally different historic trajectory of course so if you look at stone tools for example that the Neanderthals made three hundred thousand years ago were in their peer and when they disappeared thirty thousand years ago those stone tools look pretty much identical to each other all technology across the whole range of Neanderthals is also pretty similar when modern humans come all that changes technologies start changing rapidly and becomes regionalised in different regions modern you must make different tools and we have after all existed only a third of the time that Neanderthals have existed on the planet and I think we agree that our technology today is quite different as 50,000 years ago there are other things such as figurative art figured or that really depict things comes only with modern humans and of course this thing that we spread across the whole globe this earlier forms of humans lived for 2 million years in Africa Europe and Asia never trust water Larry don't see land on the other side then can modern humans and in 50,000 years when colonized not only Americas Australia but every little speck of land in the Pacific so the whole food ëcause be that some of the sort of reason for this very special thing what happened in human history would be hidden in this catalogue of genetic changes that characterize present-day humans so if we now just to illustrate this take a very strict definition and say what are the changes that happen here that your best of our knowledge is in hundred percent of all humans today when we look at all databases we have access to yet now the tools and and incidents look like the Apes then that catalogue is not a very big catalogue of things it's 31,000 substitutional difference is some insertions and deletions and so on so you can scroll through them in the computer in a few hours so it's for example only around 3,000 regulatory regions now it's of course how you define regulatory regions but if you take one definition of them it's something like 3,000 changes it's 96 amino acid changes and I just focus on them for a second to sort of illustrate how you can go after this this is not to say that regulatory changes are not perhaps even more important so these 90 Vic's are actually located in just 87 proteins because some have several changes and you can of course now start saying could some of these be important hopefully there will be many experts on disease we will sort of find interesting things here we are cost bias two things that's saying things in the brain might be particularly interested so we were quite interested when the Allen Brain Institute actually looked in different parts of the developing human brain and looked at these genes that have amino acid differences how many of them are expressed there and as a control genes with silent changes that don't change the amino acids but otherwise a recipe antennas exactly the same way fixed in humans ancestrally Neanderthals and so on and found that only in the proliferative zone where these stem cells divide to make new neurons do we see significantly more of this amino acid the proteins that we've changed amino acids expressed and these are of course signals that rely on few proteins it's actually relies on five proteins that signal and quite strikingly three of those five proteins are involved in the kinetochore and in the spindle that surprised me a lot but there are of course indications that say the mitotic cleavage planes of the stem cells in this epithelium and euros are born the term is say how many cell divisions you have and what types of neurons you make so this is just sort of idle speculation but perhaps these three proteins should be particularly interested in studies in brain development what this change is meant but that brings us to the last question and I had and that is this question how should we go after these types of changes that are essentially fixed in humans yet or perhaps involved in human specific traits where a per definition have no sort of animal model and I've gone around for years making jokes in a talk like this and saying what we want to do is take the nano tonyi and put in a transionic human and the human allele in a transionic kim and said that we can't do that of course we have to think about something else but now it's suddenly not so ridiculous anymore because there is people like your church a professor at Harvard no less that go around and is even more extreme like this and say we should clone the underclass you should put in all these changes in our catalog in earth stem cell and make an individual and I don't know why we are sort of forced to discuss this I think is technically impossible and ethically unthinkable of course but it doesn't sort of solve the problem of course we sort of how will we go after these things and I think that one thing that will happen soon but people here are much better position than me to think and discuss this is to say that I think in the future we'll be able to find back notations in humans when millions of people with higher genome sequence when they go into the doctor's office locals know that all mutations compatible with human life exist in the human population because the genome is small enough and we're enough people there but I think it will probably become ethical possible to find ways to go out and sequence where and study these individuals well that's a bitter way you can engineer these into IPS cells of course and we and others are in the process of doing that to study differentiation of cells in in vitro and what I want to make a little bit of propaganda for for the last 3-4 minutes is then that one could perhaps after all use model organisms such as the mouse and I want to illustrate that with one gene that we have studied since 9 years now it's a gene called Fox p2 on chromosome 7 here and it caught our interest because it's a trap encodes a transcription factor that when one copy is mutated it's not early to severe language and speech problem in human families it's also a very conserved protein that's encoded so if you look in the mouse it has only one amino acid difference here all the way the chimp but interestingly two amino acid differences on the human lineage here they are close to each other in one exon so it seemed very interesting first of all to look in the Neanderthal genome and the mythology note to see if these changes are shared with them and indeed it turns out it is so these changes are carried also by Neanderthals and Denisovans so they happen back here so they are not a modern human specific one but they are still interesting of course if they have something to do with speech and language or human specific traits so what we have done already some years ago is to engineer these two changes into the human into the chimp Fox p2 gene so since this is such a concert protein we now have a mouse that essentially makes the human protein from its endogenous fox p2 gene with one other very conserved change over there so you then have this Mouse and you have the problem that you want to study human specific traits speech and language so we try to speak to the mouse but it didn't lead to anywhere and so instead we said this is a very conserved protein so it could be anything in the phenotype really so we were very lucky to work together with this Mouse clinic in southern Germany that do a very comprehensive screen of them the homozygous knock in mice with their litter mates that are wild-type so do look at very many phenotypes as to give you a feeling for it to sort of going through them here metrology would have UI function all in all they looked at 323 phenotypic traits not at all all independent of each other many are across highly correlated but it's in a very comprehensive phenotypic screen we had two independent knocking lines we made and are only two phenotypes that were significantly different between knockings and littermates the first one is that the humanized mice are slightly more cautious in human Ireland's measured so that you have a social group here you open doors and you the mice can go in and explore an open area mice feel more safe along the walls so the humanized mice stay more at the walls whereas the other ones do mostly that but also venture in the mid layer but it's just a transitory phase it's just the first few minutes are slower to explore the middle of the open field than the wild-type mice and no clue what this means whatsoever the other phenotype though arose by interest and that is that they vocalize differently there's no way to say they vocalize in a more human-like way they but you sort of measure that by taking two weeks old pups out of their nest and a peep in the ultrasound area here an amount amount comes to bring sand back into the nest and our number of features in the sonograms where the humanized differ from the wild-type sometimes it looks like sort of a dominant trait I was codominant so this is very interesting so to support that this change is might have something to do with muscle control in the oropharynx or something like that but the frustrating thing is that they're sort of hardly anything known about the neurobiology of Mouse localization because but you after all now have an animal model so you can take out new roma precursor cells for example you can differentiate them in vitro and you will find here that if you do that from the street and they actually grow out longer new rights the things that we become dendrites and and axons and in the live animals you can also see bigger than Hritik trees in the striatum you can do electrophysiology and slices from these things and you can see that long term depression we're sort of the neuronal excitability goes down after a high-frequency stimulation sort of model for learning and memory is much stronger in the striatum in the humanized mice and in the non juveniles mice so what we then know about this at an orchestral collation your more dendrites you have this increased inactive plasticity and you have decreased dopamine levels that I haven't mentioned the sort of generator hypothesis the reasonable hypothesis is that we would have something to do with cortical basal ganglia circuits where the basal ganglia receives input and gives output to cortex and the brainstem that has to do with motor learning of and or other sort of things that support this the regions in the brain where we see this bigger than trajectories just very recently then previous graduate students have worked with one grayble at MIT and looking at motor learning in these humanized mice so they do different tests where the mouse have to sort of learn to go towards a signal to get some reward that can be tactile signal here or a visual signal and under certain paradigms these mice learn in seven to eight days what the wild-type mice will take 11 12 days to learn and by doing various variations of this this is not my fields I asked to relate what they have found they have sort of made it likely that this has to do with a switch from sort of what they call a declarative phase of learning where the animal needs the cue knows a goes towards the lamp and then after why you can stop turning on the lamp and it will know it will go to the left it will sort of come to precede your face we're sort of endogenous lino Elias turned left to get my reward so they illustrate this by to me by saying if you think about how you learn to bicycle in the beginning you think about how your bicycle and you're very bad at it and then after a while you sort of automated it and you get very good at bicycling and this correlates with the activity shift from the medial part of the striatum to the lateral part of the street so this generated sort of hypothesis that we would see some difference and synaptic plasticity medially and laterally so we then went back in the electrophysiology in the minds and in the latter part of the straight and we see this increased synaptic plasticity increased Ltd whereas when they then look medially we see no effect at all or if anything in effect in the opposite direction but no significant such effect so this seems to sort of support the current hypothesis that these amino acid changes have something to do with changing cortical basal ganglia circuits to make for faster procedural ization sort of automation of learning and perhaps them with aspects of learning speech and language and you can of course make a nice sort of speculation and say the sort of what we learn to do when they learn to speak is that we automate coordination of muscle movements in order for rings to produce articulate speech and it's probably the most sophisticated muscle coordination that we actually do in our life and a form of thing that say apes are not able to do I should accelerate a little bit here I should just say in the fox p2 gene we also find a regulatory change it seems that it's very conserved all the way to frogs get changed in modern humans and it affects the pol 3f2 sides where we can show that ancestral version actually binds less of the dimer and also and it's more efficient in driving expression in a model system but we don't know anything more about that but it somehow seems that you have these amino acid changes and perhaps a regulatory change than there so this is a lot of work over several several years of course and in the end we sort of have to study the changes I think in this systematic way back into the organisms so then hopefully maybe in the end understand something of what set humans on such a very special track among all other primates so I hope I sort of convinced you that if you're interested in in human evolution of recent changes in humans it's very good to have the genomes or our closest relatives because you can sort of see what have happened on this line here and the future also here when we're more dinos here but it will not be enough to have the genus the genus oh yes the two locals what we had to do in the end this sort of functional work and I think the most reasonable well forward air is after all a humanized Mouse so the many people involved in this many more than I can mention had already mentioned that in an analysis consortium Jim Mullikin and his group here played an important role I also want to mention yes one person Matthias Meier and the group that came up with this single-stranded library protocol that really made it possible to generate these high coverage she knows from these extinct forms of humans and with that I thank you for your attention we have microphones in each aisle and so if people have questions I'd ask them to please go to a microphone yes you mentioned at the beginning that mitochondrial DNA did not support an mixture hypothesis and later you said that wouldn't this imply that the DNA from the Neanderthal was male yes so that would be one explanation for it it's also compatible with that this is just stochastic variation and mitochondrial genome is inherited as just one unit so it's rather easily lost if a female has no female offspring it's sort of her lineage is lost so the more boring explanation is that now we also see on the X chromosome reduced contribution from Neanderthals when we first saw that I said that's clear it has to be male gene flow because you know males transmit only to half their children I transmit an X chromosome the other ones get away but then we've seen this of the deserts in other chromosomes too so that made us shy away from saying that this is mainly inflow but if I would guess I would say it's mainly maize okay and doesn't this conflict with that with what you said later on that Neanderthals had less probably less fertility and what the hybrids would have had less fertility yeah so I think in the hybrids this would suggest that the female hybrids may have infertile but the male hybrids may have reduced fertility in the analysis that led to the testes specific gene standing out in speciation and model systems hetero hetero chromatic regions can be very important so do you see any any signals pointing you towards those those non-genic regions and the only analysis we have done is that in this desert what genes are enriched there so they might well be we would not have seen it as we all analyzed it much of the heterochromatic things or perhaps also repeated or so there we have really mapping problem from our short little pieces so we can only statistically say how many copies of a repeat is there we cannot really reconstruct the array of repeats so sláinte at your the trying to identify humans with back mutations as you call them is not not a crazy I mean it's absolutely gonna be probably seasonable in only a matter of years if we can get all the data aggregated in a way you can look specifically but when you when you how are you imagining then taking that knowledge to sort of the next study are you I mean if you had a person in front of you with some of these I mean are you gonna study the individual you're going to study their cells you're imagining just immediately going to mice but it would seem to me you'd want to have the opportunity of taking advantage of having a personal I would after old hope that one would find this in cohorts with a recall possibility what would you do with those individuals well that of course depends on what you know what regulator element is affected where you would wanna fit that with some functional insights yes I did that yes and before we get to that I would propagate that on genotyping arrays these are just 31,000 snips why don't we add them to genotyping arrays today so we can pick them up quicker actually I'm a little troubled to understand that your statement that Neanderthals didn't exist in Africa at all they came out of Africa 300,000 years before none of them stayed or they only developed or they radiated they couldn't walk back to Africa this is my sloppy language I guess is the ancestors of Neanderthals that come out of Africa so there are things that near a paleontology we called Homo heidelbergensis that you see both in a free outside Africa and the idea is that they evolved into Neanderthals but the morphology we used to define the under Klaus has never seen that's something that appears in Western Eurasia and we now have a little bit of DNA sequence from the Homo heidelbergensis that's four hundred thousand years old so we've begin to be able to reconstruct this perhaps the DNA evidences I I can see that that link being there but that we haven't found a Neanderthal in Africa could be found tomorrow yes but I would still be surprised if one did that's because yes there has been after quite a lot of things found also in Africa by now okay well with we have a one more question last question just quickly the the Fox p2 story is so compelling are there any other kind of specific gene function stories that are evolving in your lab well so we are now trying to put in a few others of these more recent changes into mice three of them that we sort of bet on will have some phenotype there are other studies in mice that the come along has been this either gene that is to do with sweat glands and hair structure that's a variance along humans today that have been put into mice and gave a sort of a reasonable expected phenotype and even expectation of phenotypes that we then could go out and check in the human population and and and find them so I think it's not unreasonable to suggest that mice can be for some things a good model but it has of course limitations okay well please join me in thanking sponte fur
