Perspectives on isotopic and ancient DNA research on migration by Hannes Schroeder

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    Interdisciplinary Approaches to Migration Research 2017/2018: a Pufendorf IAS initiative aiming to explore new conceptual, theoretical approaches as well as methodological innovations to address processes linked to migration.

    This presentation was given as part of a seminar under the initiative The Role of Genetic Geology and Archeology in Migration Research.

    Speaker: Hannes Schroeder, Natural History Museum of Denmark
    Find more information about the Migration Initiative

    okay good afternoon I would like to welcome you on behalf of puffin of Institute's migration initiative I'm the coordinator of this interdisciplinary seminar series here on migration and today's topic is for some of us it's really beyond our disciplines but for some of you probably you're more familiar with so the theme is the role of genetic geology and archaeology in migration studies and the ways in which these methods could be used or what are the challenges in using such methodologies when it comes to studying migrations in the past and without taking too much time I would like to just introduce our speakers for today so Hans Schroeder is from the Nature History Museum of Denmark University of Copenhagen and second speaker Bettina body and she's from the Institute of European and oriental studies and at academy austrian academy of sciences and she's also an archaeologist specializing ancient egypt okay now I can leave the floor to your Hennis thank you very much thanks thank you very much for the welcome thank you for the introduction it's great to be here that a little little trip up from from Copenhagen so yeah well the brief was to tell you a little bit about how in archaeology we use isotopes in ancient DNA to to look at migrations tell you straight away there's not going to be a lot of isotopes in the talk I did isotopes in another life but I'm mainly now doing ancient DNA and that's what mainly the talk is going to be about so i termed this if ancient DNA revolution in archaeology a Swedish colleague of yours Christian Christensen has as coined that phrase another revolution in archaeology akin to the kind of radiocarbon revolution and whatever we had and the subtitle is kind of migration makes a comeback and I think Patino's going to talk about Jen you know the history of migration research in archaeology so I'm not going to say too much on that just to say straight up that there was not always a popular concept in archaeology and it has changed over the years so what I'm going to talk about a little bit therefore is is any insight into the history of migration as a concept in archaeology and I'm going to get into how we use now ancient DNA in order to to study migration and population movements in archaeology are going to give you a couple of case studies - if I have time one if I don't and I'm going to talk a little bit about the challenges that we face or the criticisms that we've faced as a as a discipline I should say I was trained as an archaeologist but have been for the past eight nine years or so been working with with with genetics so in DNA so I understand some of the criticisms that are generally coming from from colleagues in archaeology so what do we do archaeologists what they're interested in generally interested in in in culture change and generally looking at material culture and then trying to come up with some sort of explanation as to why that change happened in the past you know put very simply and four at several points in the past migration was a very popular way of explaining culture change particularly I'd say in in the early days of my culture history approaches so we're talking the archaeology of the Gordon child and and and and those kind of people where migration was used as the mechanism to explain cultural change so one people on one group of people moving into another area and somehow kicking an action a chain of events that led led to changes in material culture changes in lifestyle changes in foodstuff being used and so on and so forth now this is kind of exemplified by particularly in the early days kind of these cultural historical approaches where you know here you have a table where different cultures are expanding and retracting and they have different you know kind of material cultures things associated with them you know here geon's build starting build palaces and so on and so forth and those kind of approaches also kind of culminated in kind of hyper diffusion 'us explanation so you had you know people saying that Stonehenge was built by Egyptians or you know other even crazier kind of suggestions being made of links between different people and again migration was you know the way that this should have should have happened then it really fell these kind of approaches fell out of favor particularly in the 60s 70s the post perceptual approaches in archaeology I don't know if that's a concept that you're familiar with that's so and I kind of got did my undergrad at the tail end of these of this kind of properties post perceptual approaches and migration really disappeared from textbooks and from you know explanations that were that were inferred people emphasized much more kind of or talk to us or you know local developments or cultural developments culture change as being the cause of you know local local developments and all people ignored these types of things all together and we're you know emphasizing other things like I don't know how does it feel to walk through a landscape or whatever so one of the kind of classic examples in archaeology of this this debate and and and where migration was also also being inferred as one of the kind of possible explanation is is the spread of farming into Europe so here we have a you know relatively early from the 1965 a publication showing the different dates of farming settlements in Europe and they start in the you know with the black dots in in the Near East and Turkey and then moving a little bit later you have them appearing in the Balkans and then even later you know moving into Central Europe and then into the British Isles and so on and so forth and that's bad you know you know that that process kind of spent the best part of ten thousand years or so starting perhaps twelve thirteen thousand somewhere in in in in the Near East and then moving into into the British Isles and arriving there perhaps I don't know four thousand years before present and the big question in archaeology for a long time had always been well this process was this down to a movement of people or was it down to a cultural transmission so a movement of ideas right and either you know you could support either argument with with you know with the with the archaeological evidence now we're you know kind of isotopes to some extent and then ancient DNA comes in is this that there are new methods that allow us to study migration or the movement of people by not looking just at material culture but by looking at the remains of people themselves and so the old saying of pots on art people you know that kind of always comes up in this context as well to say that if you're just looking at material culture it tends to be very difficult to try and infer whether this was you know culture change was down to movement of people or or to a movement of ideas but if you analyze the remains of people themselves you may have a better chance of trying to trying to figure those things out isotope analysis are useful in a sense that they kind of relate to a lifetime so you can establish local or non-local status of an individual you can thereby infer whether that person migrated during their lifetime but it doesn't really tell you that much about a population or an ancestral group or you know kind of those those those different levels of influence and this is perhaps where ancient DNA analysis comes in I can't tell you where an individual necessarily was born but it relates to his or her ancestry so the ancestral composition of that of that of that individual and the population that he or she belonged to and it can be used to infer migrations in the past and if we take this I'm jumping ahead here this is kind of how it works in a cartoon kind of fashion just to show you that we start off with a you know a bone or a tooth from hopefully a securely dated archaeological context you extract DNA you sequence it on some fancy machines you get sequence data out of it this is what it looks like so basically DNA being composed of four letters a C T and G and what we're interested in is really the variation between individuals or in this case what you know what you generally do at first is to map the liver and bits of DNA that you sequence to a reference and you try to see you know how it varies from that reference so here for instance just to illustrate this to kind of get an idea of what the data is that were actually looking at so here in this case the reference that we used it's called you know a human reference genome and all the bits of DNA that we sequence from this particular bit of bone tend to have you know a T in that position whereas the reference has a seat and so that's the kind of data that we're looking at single nucleotide polymorphisms as they're called mutations you can loo use you know other types of data but that's mainly what we're what we're looking at and then we're feeding this type of data for one individual for several individuals into various programs that allow us to infer things like the ancestral composition of that particular individual we can look at we can make inferences about demography so here in this case for instance this is a plot that illustrates changes in effective population size over time for I think in this case I think it's yeah I think these are humans actually and Neanderthals and Denisovans and there are other things that that one can that one can do as well so here's just a very brief list I mean while relatively long lists and so the first very you know kind of straightforward thing to do is simply determine the biological sex of an individual you just have to look at at the sex chromosomes you can look at phenotypic traits if you're interested in those so you know eye color and skin color and those kind of things we can look at kinship patterns so how people are actually related genetics is of course the science of relatedness so you can you can do you can try to do that determining ancestry and we're gonna look in a little bit more into that in just a few minutes then how you know how that can be used to look at human migrations demography local adaptations is another thing so how you know humans and environment interacted other things that people are getting into now are you know things like finding evidence for ancient pandemics pandemics through pathogen DNA other people are not interested in humans at all but in animals so you can look at the evolution in spread of domesticated animals for instance all those type of things here's a kind of again cartoonish timeline of the history of ancient DNA also just to give you give you an idea so it kind of started in the in the in the 80s with this study of a quagga it's a kind of half horse on a zebra type beast and it the first kind of big step in ancient DNA was the invention of PCR so that's polymerase chain reaction which allows you to amplify small bits of DNA but I also you know is a problem in a way because you also amplify contaminants and so some of the first studies looking at mummies for instance we might hear about later on as well as you know sensational claims about dinosaur DNA and this is why I put your acid park here and you know getting ancient DNA from amber and so on probably we're all down to contamination as opposed to you know the real thing and this is why I call this the dark ages because really really almost nothing from this period you can you can really rely on as a result because of these issues with contamination and so on but then it's not entirely true I'm sure there were some very good studies among those as well but then there in around 2005 so roughly 10 years ago so um and simply a technological change happened which was we meant that we could sequence DNA in a very different way in a fundamentally different way and that could produce a lot more data within a short amount of time and then you can see that after that you know not too long after a number of very kind of groundbreaking studies happen so you know the sequencing of the first full genome of a mammoth for instance just three years after first ancient human genome which we sequenced in Copenhagen in 2010 in and out our genome which was published in the same year revealing you know fascinating facts about ourselves who we are and how we relate to to to our cousins the Neanderthals the Denisovan genome you may have heard about the Denisovans they are kind of an hitherto unknown hominin species that was just identified by sequencing their genome from this tiny finger bone the oldest genome today it is about 700,000 years old and it's from a horse that was found in the in the Yukon also done in Copenhagen and then about you know a couple years ago people started to do really population level studies so not just looking at single individuals but looking at literally hundreds of individuals and of course that gives you much more power and in terms of what you know what you can say and those studies you know one of the major themes in those studies was migration so here's a very kind of you know just an overview of what's been happening because of these technological changes in DNA sequencing it just shows the the the number of ancient genomes so human and hominin genomes that have been sequenced over the last few years and you can see that in terms of you know modern human genome so we're talking here about anatomically modern humans but ancient human ancient genomes we've got over a thousand by now and and hundreds are being added every year so this is kind of the situation that we're in at the moment like I said the reason for this is this technological change it's often referred to as next-generation sequencing or high-throughput sequencing it's simply a very powerful way of sequencing DNA and you can produce roughly one here so you can sequence one human genome in about an hour so that's three billion base pairs and that would have the first human genome that was finished in 2003 it took you know I want to say a decade and it costs an incredible amount of money so now this can be done in in no time essentially this is just a side slide just to say that there's a little bit of a bias in terms of where the genomes are from that have been sequence ancient humans ancient human data mainly in Europe and this is partly to do with preservation but also with you know the fact that in Europe we have the leisure and the time and the money to do this type of research there are a number also from the Americas and there are there's only really one and then a few more from from from one from East Africa one and a few more from Southern Africa so you know that's that's again that's kind of the picture that we're dealing with here so let me then get to this question then how do we infer migrations from genetic data now this is now already you know a fairly old schematic here showing the world and showing simply if you just take the mitochondrial genome it's its own little genome that lives in the mitochondria the powerhouses of the cells and you just look at though at the DNA you can start reconstructing or a kind of global level the migrations of anatomically modern humans Out of Africa and then as you know how they spread across the globe and this is migration and it's you know kind of the the biggest level I guess these letters incidentally were completely arbitrary that just referred to haplogroups as they're called so groups of individuals that share the same haplotype as it's called so the same motif of DNA in this case mitochondrial DNA you can also start to date these migrations here so based on you know the if you miss this concept of a molecular clock so you can take you can assume a certain mutation rate the rate at which these genomes change and then you can try to date these these divergence points here so going from you know perhaps 200,000 years ago in Africa into Eurasia and Europe maybe 80 thousand years ago or so into the into into East Asia and then into the Americas maybe 20,000 to 15,000 years ago now this is you know this is interesting and and and tells us about kind of the the spread of anatomically modern humans across the globe but archaeologists we often you know we tend to be interested in migrations at a much smaller scale and and the interesting bit is that ancient DNA as it's been developing over the past ten years allows us to do that as well and here I just want to show you a couple of slides of the kind of underlying principles that that that make it possible so one of the first thing to note is that if you look at human genetic variation so just simply genetic variation of humans across the globe you'll find that it is geographically structured and this is simply down to the fact that people who live further apart have less chances of mating than people who live closer together and it seems it seems so obvious and in in in genetics it's called isolation by distance that's the that's the concept that we're dealing with here so if you look at this you know using an actual data set this is a principal component plot which was you know now published oh well ten years ago by now a decade and this was really I open her for for a lot of people in the field in the sense that this here shows roughly a thousand individuals from from Europe modern Europeans and you can see then they have been typed at or sequence if you want but typed using a particular technology at about I think six hundred thousand different positions across the genome and if you plot the variation along two prints of components and you reduce it to these two dimensions you will find that they tend to cluster in in these groups here so here you have Spaniards and Portuguese people Italians the British Isles and you know long story short of you know the interesting bit is that a genetic map tends to mirror a geographic map of Europe so there's a close correspondence between Geographic and genetic distances and the same works for other parts of the world too now in terms of ancient DNA of course this is interesting because you can start using this and we still use you know these type of reference datasets in order to in order to infer migration so the first example really OBE of this or one example is at CD Iseman it's was this genome was sequenced three four years ago and if you try to plot let's see on this genetic map of Europe you'll find that he actually plots with modern-day Sardinians sorry those of you who don't know Etsy I'm sure you all do but it's the IceMen lived around you know five thousand years ago or so and the question you know now would be so why does Etsy plot with with Sardinians does anybody have an idea let me have face value if you just look at it like this I mean he was found here Switzerland was a Switzerland on the genetic map here's Italy I think that is he Italian or is he Swiss I can never remember but he was Austrian as Austrian right even even even even even worse so I don't know and so but he was you know found in this in this area here there's actually an Austrian right there eighty and you know but he plots with Italians rather than rather than with people up there so any pardon not far yes well it's true although this is the interesting bit here is this is mainland Italy and these are actually you know they're off on their own from Italians here and these are so these are not mainland Italians but they're Sardinians particularly specifically very much mixed mixed with whom yeah well they're armed I mean this is what you say is it is interesting is also true but what I should say here in terms of the how these samples were selected and this is important point to make they they didn't just sequence anybody that they ran into in the street or tested but people who could trace their ancestry at least three generations back so we're talking here you know about you know if you had a recent immigrant of course you know they would not necessarily plot on this on this map or if you had admixture individuals you know they would also not neatly fit into these clusters but they would fit somewhere else now well but looking at I'd see again here so I guess I mean one of the you know what you might think is is that well he did he come from Sardinia no but what you know that wouldn't make any sense why would he why would he the other explanation is that that the genetic landscape of Europe 5000 years ago look very different to what it looks like nowadays but that for some reason it was preserved in Sardinia and that makes sense it's an island it's isolated there was maybe less admixture over the years recent admixture fair enough but maybe over the years less admixture which means that Sardinians kind of still look like what people looked like 5,000 years ago genetically in in Europe whereas the rest of Europe has changed quite dramatically so that's kind of the the interpretation that we're going with and it you know it's just to say that that genetically at least that the past was a you know a very different country now what a lot of the studies in ancient DNA that we and many colleagues have been have been conducting and I'm going to show a number of case studies that were produced by different labs in in Europe mainly in Europe but also in the States that kind of tried to explain or understand you know what kind of processes actually gave rise to this structure that we see today and why did it change from you know 5000 years ago so if we look then at again the principal component plot of Stone Age Europe so here we're talking ten thousand years ago roughly hunter-gatherers you know in Europe here in gray is our the modern reference populations again modern Europeans these are populations from the Near East here the British Isles and these here in the colors the colored dots are different hunter-gatherer populations so here we've got Scandinavian hunter-gatherers so where we are right now Eastern hunter-gatherers Western European hunter-gatherers and so on fourth so the first thing to note here when you look at kind of the genetic landscape of Stone Age or hunter-gatherer Europe is that they don't tend to overlap with modern populations and the second thing to note is that there is some structure among them so they don't all cluster together but they you know are you know show structure between those populations now what happens if we go a bit forward in time and this year is simply just to explain that is a different way of showing the same thing is called an admixture plot so here you have one individual each line is one individual then populations and you have different answers to ancestral components that make up these individuals now if we move forward a little bit in time and we go to the Neolithic so now we're talking the coming of agriculture you know in Europe you see that they tend to plot and this lower part of the of the PCA plot these so these are early and middle Neolithic populations and at-sea plots somewhere you know one of these guys is Otzi he plots there some somewhere and they tend to here overlap with these populations you can see them there in the background from from Sardinia now what this indicates clearly is that there that the hunter-gatherers and the later Neolithic populations were not the same people right you see that they're genetically quite distinct suggesting that with the coming of the Neolithic and all these culture changes that we associate with it from from the archeology we're not down to simply a movement or you know the change in ideas but but involved actually people moving probably in areas from you know from the starting in the near East now another was something that I always ask my students as well so if these guys originated in the Near East how come modern near Easterners don't look like them anymore and that's simply the same process that we have seen with that see that you know their genetics were also replaced in the intervening five six thousand years or whatever now you can play this game as you go further in time here we're looking at the Bronze Age another period in European history that was associated with really drastic kind of cultural changes and you know even associated and this is this is something that is highly you know a bit more controversial so the links between genetics and language but it's associated with indo-european languages the Bronze Age that is and what we see here is basically if you move on you have another population here from from more Eurasia I called the M nya and what we see is that really the there's one one little bit missing but essentially that modern Europeans are essentially a mix of these three all right you can kind of see modern Europeans here they there are ten they tend to be a mix of these three kind of ancestral populations hunter-gatherers Neolithic farmers and then the bran the Bronze Age kind of step populations that that that were coming in from the east and that's kind of what gave rise to you know the this genetic structure that we see nowadays plus I suppose the these isolation by distance mechanisms that I described earlier so in terms of the you know archaeology or you know what that what that tells us I mean you could argue well this is old news in a way because not only Merrigan Berta's but you know if we go back much further back to the 20s and and early 20th century people were arguing for you know people moving and and bringing in as she described it you know kind of causing major ethnic shifts in in the in the in the in the population now the interesting bit is and this is one thing I would like to bring across is that we're going to talk about the challenges later but that ancient DNA or DNA generally can you know not only allow us to infer that immigration happened but it can do much more so here is just a very simplistic example of that it allows us to kind of determine the timing of particular admixture events as well so here you know a simple example of the colonization of the New World they've got a population there of Native Americans of course already existing Spaniards in this case moving in ad mixing with the local population and what we can do and this is just a you know skin Ematic example but we can pretty precisely date this admixture event within an era by looking at the lengths of these different ancestry ancestral tracts in in a person's genome and that's simply because you know if they're very long these ancestral tracts then it relates to a rather recent admixture event but if you're if they're very short it relates to an event that that flies you know far far in the past simply due to recombination so that's one thing that one can do another thing that one can do is in association with you know the migrations you can start to look at trying to infer ancient signatures of positive selection so local adaptation so how did people adapt due to certain changes in in lifestyle forests for instance and the famous example of this is always luck taste persistence or our ability to digest milk after after after weaning and here's an example of that showing that with the coming of our GU culture you know you suddenly have in different parts of Europe this lactarius persistence allele so the allele the specific allele that conveys lactase persistence you you just have that rising quite significantly and it's interesting to see that playing out in the in the in the genetic data another just another example of stuff that can be done now not looking at the human DNA but looking at pathogen DNA people are also working on trying to infer the spread and evolution of pathogens that traveled with humans for instance so here you know again instead of recovering human DNA you would recover pathogen DNA and you can study transmission rates and and virulence a particular pathogens plate for instance you can see how they're related and using that you can then try to reconstruct how a particular pathogen spread across the globe and when and so on and so forth very exciting very exciting area of research and now I'm in the last how much time do I have ten minutes or so then I have time to squeeze in a little case study another case study that's actually going to be published today so if you're interested it's a paper that that we've been working on for a while looking at a completely different context but just I'm going to give you you know this is another example of how we use ancient DNA to infer to infer migrations and here we're looking at the Caribbean Thainess also indigenous inhabitants of the Caribbean and so what the questions were there that we had was well firstly where did the ancestors of the of these people originated that first people the the Caribbean we also had questions relating whether we could infer aspects of their social organization and demographic history and I might get into that if I have time and then importantly we wanted to also know how present-day Caribbean populations relate to these to this ancient individual in the Caribbean it's a bit tricky to do ancient DNA it's a it was very hot as very DNA doesn't keep very well but we were able to find a sample out of many that we looked at and that one was from the angle of eleuthera just here at the very top of the map in the Bahamas and it came from a cave this one preacher's cave it's called on the north end of eleuthera and in the around 2005 and six I think archaeologist colleagues of ours excavated several burials in that cave and we were able to obtain one tooth that we could try to use to to reconstruct what you get DNA out of and it worked surprisingly well for for this you know the rather difficult context and so we managed to get a high coverage genome from this individual 12-point Forex coverage is very good for an ancient genome means we didn't sequences only once but twelve times over and we could use this in order to infer firstly the origins of the migration that led to the peopling of the Caribbean or one of the migrations perhaps and so what we can see here on this plot for instance is simply a map showing up around I think it believe it's 50 different present-day Native American groups and we show the genetic affinity of this genome from the Bahamas to these different groups and the you know the darker the color so the more red the higher the genetic affinity in what we can see is that they show the greatest affinity with these populations here from the northern Amazon indicating that the Caribbean was first settled from South America here or not first but that the individuals that this were the population that this individual belonged to originated in in this part of South America and this tree shows exactly the same simply showing how these different populations are related in a phylogenetic tree and here the the ancient I know fits with these are awoken speakers from northern South America so that kind of you know provides one answer to two to the peopling of the Caribbean she was female it's another thing we we found out and then in terms of the demography this is getting a little bit complicated but bear with me and what we wanted to know was yeah if we can say anything about the development of that particular population how it changed over time and one thing that you can do is you can look at so-called runs of homozygosity so you're homozygous in your genome when you got the same call of DNA from your moment from your dad and so if you have long stretches of this that kind of means that you come from a bit of an inbred population simply because you know there's a lot of DNA shared in that gene pool so if you and we can use this in order to infer aspects of like past restrictions and population size for instance so in this plot here we can simply what we did what we plotted these restrictive these Runza from my sagacity here and we divided them in different bins so we have very short runs of homozygosity so short tracks whether you have the same copy for mom and dad and very long ones and what we see here is that on this end of the very short runs oh this is wrong it should say short one sorry lots of short runs are for my sagacity and they're indicative of a ancestral restriction in population size and this fits very well with what we know of the peopling of the of the americas people in smaller groups probably moving into the americas and then the serial founder effects happening again and again with you know restrictions in population size and that's exactly what we that's what we see here so use the tie know which is here in in in the in black that line it has basically the same trajectory as other types of other Native American populations but what's perhaps more interesting is the other end so the long ones the long runs of homozygosity they are very low in this particular individual and we inferred from that that basically it shows no evidence of recent inbreeding or isolation and that's interesting because this individual lived on a very small island like five hundred square meters so you might be wondering you know if you're looking at the opening islands for instance nowadays people there tend to be a little bit inbred more inbred in a grand scheme of things but that didn't seem to have been the case here in in in in these islands and so that kind of indicates that there must have been some mechanism in place where social organization you know or social networks or whatever that extended for beyond the local scale otherwise they couldn't have you know kept these these high levels of of effective population size essentially so lastly and what we looked at with this particular study was this question of you know how much of tyno ancestry has survived in the Caribbean or in Caribbean populations today and if you look at textbooks of kind of American history or Caribbean history in particular the kind of story that you're often faced with is is that indigenous populations in the Caribbean in particular basically were during close to extinction or to extinction within a hundred years of the arrival of Europeans through disease through resource deprivation through forced dislocations through you know all kinds of all kinds of different processes but there are groups in the Caribbean and elsewhere who strongly self-identify with being tiny or being indigenous to the Caribbean and you know they would have argued for for for for fulsome continuity so against this this myth of extinction now with an ancient genome what's nice is that you can actually directly test this so here we have basically a genome with its you know 22 chromosomes here plot it and we colored in well this is from a different study but they colored in different ancestor tracts on these on the chromosomes European and Native American and sub-saharan African and on average modern Puerto Ricans for instance have 15% of Native American ancestry roughly and the question then had always been you know was this ancestry native to the Caribbean or did it come from from elsewhere there are lots of there's you know quite a bit of historical evidence showing that Europeans move people around from South America and from other places into the Caribbean so with an ancient genome you can actually try to figure out whether this blue these blue bits here are actually related to the title or or not and so that's then that's what we did and this is what these graphs here represents so what we found was that the Native American components in modern Puerto Ricans and also other populations are actually very closely related to the ancient I'm not suggesting that you know suggesting that there is an element of continuity so that Tyner DNA has has really survived through the present-day okay so now I'm just I'm gonna wrap up and I'm gonna there's very briefly in the last two or three minutes talk about a little bit about some of the challenges and critiques that people have been or that we've been facing and that on the one hand there is this idea of essentialism so or ethnic essentialism so basically that we can equate a particular cluster that we see or a biological grouping of people and we give it a certain ethnic label we call them Mycenaeans Minoan so we call them Naya or we and there of course the danger that we're running into is that we end up with these grand folk narratives that you know that we're so prominent in kind of the 30s and 40s and there's there is definitely a problem with that another one is what I called reductionism so you know basically coming up with really simplistic narratives based on you know a single sample like in the case of the of the ancient I know genome and also something that archaeologists have been fighting against for a long time namely these arrows on maps you know the big migrations that go from one place to another and lastly there's sensationalism so the idea that you know for whatever reason there can be a tendency to exaggerate findings and also there is kind of an uncontrollable element of you know whatever the media do to your study once you've once you've actually published it and what they read out of it but having said that I think and here's just you know this this slide I put in as a just kind of example of the kind of problematic uses of course of this type of research and you know it can in in aspects anyway remind you of kind of ghosts of casinos a German archaeologist of the 20s and 30s settlement archaeology or zeitels nationally where he saw you know a unified Germanic material culture that overlaps with a particular ethnic groupings and that is linked with particular parts of Europe and of course it was you know was used by by the Nazis in order to justify their annexations of Poland and and other homelands during World War two just as a to qualify this though I think the power of ancient DNA is that we can yes we make links between biological signals or groupings and particular archaeological cultures but we can also see how much more complex the story can be and this is an example of this so here this is another archaeological culture that you may or may never have heard of the belt beaker culture it's a particular Neolithic culture you know characterized by these very iconic bell-shaped beakers ceramic pots essentially and you find those in various different styles across large parts of Europe Spain and Italy and into Germany and and also in the British Isles and for a long time there had again been the question okay how do these different groups you know relate to each other are they related is the same group that that produces this distinctive pottery and recently this is a this is a study that's still on bio archive but they they generated data for about a hundred bell beaker individuals from different parts of Europe here in red you can see the you know the kind of the sampling locations of those and what they found was that these Bell Baker populations are actually few genetic links suggesting that there were not one migrating population so quite the opposite of what we saw in you know some some of the other scenarios there so here we're talking maybe about some you know local developments of people adopting different what over this particular part of your style because it was on vogue or whatever and just to make the story a little bit more complicated and this is I think you know when you have more individuals available and you can look at more samples you'll find that in in the case of Britain these individuals do actually seem all closely related to each other and they seem to have not only that they seem to have replaced the earlier population so just to say say that that it's it's a you know the most samples you get it can be a very you know complex story and using ancient DNA you can start to to try and disentangle it and and add more information so just to conclude then in one slide I think whereas this was not possible you know 10 years ago but we can were now really at a stage where we can use ancient DNA to identify past migrations it's possible to tie those movements to particular archaeological cultures although not language that's that's a that's a different that's a different issue and a different talk and then in addition to this and this is I think where I ancient DNA is also so exciting is because it can provide insights into demography social organization for instance human environment interactions and so on and so forth ok so with that I just like to acknowledge some of the sponsors and my colleagues on the citizen project and how you for listening so if you have any questions thank you very much I'll take questions ok yeah yeah baths are also interesting they also seem to be and you may have guessed by and their language does come into it but they also seem to have theirs they seem to be quite an ancient population in Europe and they also tend to be genetically similar to the Sardinians and to to those populations so they seem to be also a remnant of those of those kind of early farming people that came in hi thank you thank you for the interesting talk thousands of questions that come to mine and the first one is a very general one that it's related to some of the things that you've been mentioning on the issue of reflexivity if you could say so there is this thought that comes to mind that is coming from justice and Rama Gordon the Nobel Prize in Literature when he says that every dispute about the past is a dispute about the present so how and in which way you as researchers that deal with this and kind of of research reflect upon this the the way what we're presenting here the material is going to be interpreted and the second one which is very related is by him also just as Emily says that one of the most difficult things for a storyteller when he or she is going to create a narrative is to choose the starting point and all these narratives that we have in related to human movement and and so on and so forth every time that you're going to deal with them you will be facing this so my question to you is to which extent that starting point is always crucial and complicated thanks very much I should read more Saramago's sounds like and so with regards to your first question so this is it it very much depends which context your you're working in I guess you know if you're looking at the very distant past the fact that all of us here in the room have something like between two and four percent Neanderthal mmm genetics in our DNA in us some people care more about this some some less and then you know but if you obviously if you're getting into areas where you know much more recent time periods so now where I'm I've been working I mentioned this Caribbean case and maybe that's what you're specifically referring to yeah this is this is these results are of - some individuals are huge importance because they tend to confirm what their grandma had been telling them all along and so it's important for their own identity for you know how they feel who they are you know individuals I spoke to who self-identify as as as indigenous Caribbean for instance who when in school in the US have been told know your ancestors all died out so you don't have that part of history to go back to and so therefore of course that that type of research is very powerful because it you know allows them to - to have a link so in their in those cases of course we do reflect up on it we do talk to people who are directly affected by by those where the narratives that we put out but like I said this is not always the case because sometimes you know it it tends not to affect people as directly always as in this case and like I said you know whether or not you're 2 or 4 percent neanderthal you know it's interesting for a number of reasons but it doesn't affect your daily life really as for your second question I'm not quite sure I completely got it in terms of of course we all as a point of origin if you look at it like the slide I showed for mitochondrial DNA for instance I mean if you go way back there is a unifying kind of message that we all have a common origin and that's an important one and that's one that we always tend to emphasize you know wherever we live wherever what you know whatever creed would have a religion or political persuasion we tend to ultimately go back to - to Africa as as as the cradle of humankind and that that you know that is a kind of fundamental starting point but apart from that the tricky part with drawing arrows on a map and with trying to infer migrations is that arrows on a map do tend to have a starting point somewhere on that map but it's not easy to establish that starting point not at all it's not trivial at all so you know again in terms of human evolution if you look at that scale is a massive debate going on as to you know where in Africa we originated in the eastern Africa southern Africa and North Africa with the recent find of three hundred thousand year-old how many remains in Morocco but and that's something that we do have to bear in mind and that's a that's in terms of you know if you look at those maps that we're drawing you know with with step people coming into Europe if they do have an origin but it's one of the weaknesses of having to visualize something in some way in a map you know in a map form for instance but that's not that's a that's a convenient shorthand but not necessarily an accurate way of representing what actually happens so yeah yeah yes my name is Martin den Berg Peterson from all-pole University I'm sorry to have arrived late at your talk but I did enjoy very much what I got to hear I think it's I think it's a very fascinating addition to a range of different disciplines including migration studies that this kind of new newly developed signal technology allows us to do because it's a different lens or more positivistic lens on migration processes and I think well it's just fascinating the way it can take us back so two questions and the first one is about the mixture between the Neolithic agricultural societies and hunter-gatherers I don't know if you are aware of the popular science book by a kind boys called my European family the last fifty four thousand yes but this is popularizing a lot of what you've been talking about but and I suppose this is a question then that may just you may just say yes because it confirms what you've been saying but there's not a in her work it seems to say for her depiction of science it seems as if there's not a full replacement it's not an either/or between these societies actually hunter-gatherers and fishers and and so on and aqua cultural communities lived side by side for thousands of years in Scandinavia and also interbred I mean so I think that's very fascinating two very different gene pools different societies social organizations interacting so I think you know when you go down into the nitty-gritty messy details of time you don't see these clashes that sort of come out with you look at it from a very sort of abstract vantage point that's the first question if you agree with this kind of interpretation the second one is a little bit of a challenge maybe our self-reflection because I think it adds a lot to for instance migration studies to be able to back-trace in this way but in some of also the popular science work on this there seems to be an assumption that you can jump from this to more wide-ranging statements on politics development of cultures social organizations as you mentioned as well and and quite often I I think maybe not or maybe there's also some limitations and I was just wondering whether this kind of do you recognize this sort of deterministic Drive to explain everything challenges maybe you haven't faced okay so as thank you as as far as the first question is concerned so I mean um like I said one of the criticisms or one of the dangers is that you you know represent very simplistic narratives right and so I've my answer to this would be that it it varied a lot from you know it depends where you are if we're talking about particularly kind of the Mesolithic Neolithic transition there are though you know a number of studies actually that show that you know what happened in one place doesn't apply to another when we saw the example of Britain as well with the bell beaker phenomenon there there seems to have been a replacement but in other areas that it seemed to have been the case there are there is evidence for the side-by-side that you're talking about in parts of Europe over hundreds of years there's evidence for admixture as well the mere fact that we tend to be you know a mix of these three nowadays also goes to to illustrate that on the other hand there are there is you know evidence also as we see here that that actually replacement did take place so population replacement and that the interactions were also not always friendly you know there are particularly towards the end of the Neolithic there is there is evidence for intergroup violence for instance in the archaeological record there is you know associated then also with with these with these massive migrations or population replacement so it's a it's a we're looking at a you know a pretty relatively big place Europe and with lots of different communities and so I think you know would have varied from place to place as for the second question in terms of again that's a more difficult one for me in and I don't know if I got it quite right but I suppose I I mean there are certain things that we can comment on using either isotopes or ancient DNA and then others were you know I wouldn't venture you know making comments about so already commenting on social structure based on a biology that's already pushing it you know quite far but then you said that it may that these results have some you mean in the present that it has certain effects on how people can you just repeat that part of the question yes I suppose it's a bit like in a way a version of the I asked question in that there's increasing interests in this field and in discussing the findings and you have a range of sort of popular science works that what's Mateos and the others you know homo sapiens who is who in a way I repeating a sort of a deterministic explanatory model that we also find in environmental science for instance Jared Diamond and so on and so the question is can we explain such complex social I think you already answered ok yeah yeah the answer is sometimes maybe we can explain more than in other context yeah I mean so yeah some of some of these elements of trying to work there's tendency of over interpreting your data is one that that that's definitely an issue so I would I yeah I would say it's you know Bo one should be aware of the amazing things that it can do and and yeah stay away from from things that count I mean yeah hello thank you again for a very interesting talk I'm wondering about the map about the affinities for your case study on the Caribbean of course you don't mean that that particular person carrying that genome came from the Amazon what you mean of course is that both populations come or have close close affinity and come from the same place because those are modern and that's you lack the spatiotemporal depth there in this study of course with the challenges that tropical climate has yeah no absolutely right so I in my you know rushing through it forgot to mention this is individual that we sequence the genome from is about a thousand years old from the Bahamas so you're absolutely right in saying that we are inferring here a migration by comparing an ancient genome to modern populations and what we find is that there's a greater affinity between the ancient genome and populations from northern South America suggesting that the population that the ancient individual came from shared and so had shared ancestry with those particular populations so it's it's in the sense it's it's then you know less likely that her ancestors came from yo cotton which is just you know it's 150 kilometers away from Cuba or or even you know from from from from Florida and in the Bahamas so yeah you're right but of course you can't exclude the fact if they came from there but later replacements of course yeah that's that yeah so in a way like what you're saying like what we had in the European case that you're saying that these people here who live there nowadays could have moved there in the last five hundred years that's that's true but I think here given that we're looking at only the last thousand years it's it's unlikely I think that that these guys here we're replaced in the last thousand years but it's a it's a it's a it's a you know it's a valid argument to make for about a point to make I usually work with materials like quite a bit older ah sorry yeah that's very my question comes from thank you how could tell the direction put of the peso that are united in the back in the moon also true also true and they there is nothing in terms of you know directionality that tells you that there are other types of evidence then so what we have here actually and this is where the archeology comes in of course so we know that the Caribbean was probably one of the last parts of the Americas to be occupied by humans starting perhaps 7,000 years ago or so that's when the first kind of archaeological evidence starts to appear together with the Arctic and you know this is where you know people were already established at that point here in these parts and then there are you know archaeological there's archaeological there's also linguistic evidence in this case actually that do seem to point to South America as a potential you know place of origin what I would say though is that I'm you know as we're gonna you know hopefully find a few more individuals that will work out and maybe you know a 5,000 or 7,000 year old individual I'm sure we're gonna find evidence for another link for instance form from Yucatan or from other places so it's you know it's a it's a it's a it's a complex complex history and also this this aspect that the point I made about the social organization and that communities were in contact you know the the Caribbean Sea is this is what my archeologist colleagues also tell me was not really a you know a barrier to movement but people were moving you know a lot all over the place but the you know the signal that we got from this individual it just fits with this idea that they that the Caribbean was was one of the migrations into the Caribbean originated in that part of the South America [Applause] [Music]
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