Book and Author Talk by Carl Zimmer

welcome to the book and author talk from the this year is National Academy of Sciences meeting I'm dying rippen vice president of the na s and chair of the Committee on scientific programs and today I have the privilege of introducing this year's book and author talk that will be given by Carl Zimmer a science columnist for The New York Times and an adjunct professor in the department of molecular biophysics and biochemistry at Yale as a little bit of background is ever earned a BA in English from Yale and began his career at Discover Magazine where he became senior editor before turning his attention to writing books about science he's author of 13 books and has won numerous honors including the triple a s CAD Lee science journalism award three times in the National Academies communication award twice it was the 2019 Academy's communication award for best book that brings him here today and the title of the book is she has her mother's laugh the powers perversions and potential of heredity welcome thanks so much Diana appreciate very much so I want to talk to you today about heredity which you know in the world of science is kind of something that we don't we don't need to define you know everybody knows what it already is or at least they think they do so if we could turn on this my slides um I can share them with with everyone um I'm just going to assume there we go great so so heredity is not just something now that we all talked about you know we how common is it to say oh you you know you have your your father's eyes or your mother's laugh or what have you heredity has turned into a very intimate kind of business so here is just an article from a couple years ago about how DNA gets to look find out ancestry we're becoming a hot Christmas gift we would have ads where you could get to you know a bond with your family more if you bought a 23 me kit and in the corner there understand anchor DNA that's an ad from the Super Bowl so clearly a this whole scientific approach already has become this incredible consumer phenomenon and the numbers are really kind of amazing this is a graph the Technology Review put together going through 2019 and you can see that back in 2013 pretty much nobody had gotten to look at their DNA through one of these services by 2019 it was well over 25 million it's been continuing to increase since then so what do people find out when they take these tests what are we learning about the DNA that we inherited from our ancestors well you know it's it's kind of intense sometimes so for example here is a sample slide from 23andme if you choose to find out about whether you have a variant call called efore that's associated with Alzheimer's disease so if you don't have that variant does that mean that you don't need to worry about Alzheimer's disease well you know you can see there's a lot of fine print here and so we are having to deal with this kind of information just on our own you know no doctor no genetic counselor it's just you and this thing that you bought in addition you can find out something about your ancestry now you might get a map back that looks like this so what are you to make of that what does that tell you about who you are and how your ancestors made you who you are it kind of looks to me like sort of just a lot of random circles on a map but we really invest a lot into these sorts of results especially now that these genetic tests are getting combined with geological databases online so for example here is ancestries an ant from ancestry where someone is really excited that they're related to George Washington not even descended directly from George Washington but you know that he seems to be a term a distant cousin but this counts for a lot even though we're all basically cousins when you get down to it so there are clearly like really sort of powerful emotional currents that are driving us towards this information and we might be hoping for things that just aren't there and we need to understand what it is that we think right it is and what we want out of heredity for ourselves and for future generations because the technology for manipulating heredity is accelerating in an incredible pace and in 2018 the gene editing technology called CRISPR was first used to alter human embryos and those those embryos eventually developed into babies they were born so we have the first genetically altered children among us and so we are we are we have crossed that line now and and we need to figure out what did it you know what what are those our moral view towards these kinds of interventions in the future of heredity I think you know it's really important then in order to think about the future to look back at the past because that is where a lot of our sort of assumptions about heredity came from the word heredity is is quite old in Latin it was her edit ass but it didn't refer to Reddit either way we use the word it tended to be have more to do with the you know the rights that you inherited from an ancestor property including other people sometimes and in the form of slaves the there was a sort of a notion you can kind of glean from ancient Greek writers that you know there are some similarities between the generations and but there was only the vaguest kind of speculations about why that was the case and a lot of times it had to do with climate you know that sir a climate they made somebody grow up short would make their kids short as well that kind of thinking but by the middle ages in Europe you start to have full-time professional genealogists who are drawing trees like this one which are essentially designed to justify a king having power over a country if they don't just inherit the the crown but you start to see the language of blood in other words that they inherited royal blood so now there's something such as the stuff that you get from your from your parents but it's something within you that that you got from them and from with some sort of mysterious connection I mean obviously you know we don't have blood vessels connecting us to our parents but at least to our fathers but nevertheless this idea that you know a king could could pass down a throne to his son to royal blood was a very powerful image huh and we still talk about heredity that way what's intriguing is that you know every now and then you see like somebody start to question these ideas and to start to think forward towards how we would think about heredity and so you know in this case Montaigne he actually wrote an essay which is one of my favorite examples of this in the 1570s and he wrote it because he was in his he was in his 40s and he was getting older and he was tarting to develop kidney stones and he was very annoyed at that and he wrote an essay about it and it occurred to him that maybe it had something to do with his dad because his father had also had kidney stones and so he writes it is likely inherited the gravel for my father before he died sadly afflicted by a large stone in the bladder but Montaigne is a very perceptive person and he says well wait a minute my father didn't have kidney stones when he became my father so he asked well you know why he was still so remote from the disease how could the light trifle of his substance out of which he built me conveys of deep and impress where could the propensity have been brooding all this while and it's such a great question and I mean I think that you know today's geneticists are that's that's one of the questions that drives them in their work where is it and how does it work Montaigne didn't get any answers and it was a incredibly long time before answer started to emerge and there are a lot of people that I talk about in my book who will help to sort of try try to shed light on that and actually a lot of the answers first started coming out of animal breeding so for example in the 1700s there was a farmer named Robert Bakewell and he became a legendary because he produced a new breed of sheep called a new Lester sheep which was you know very tasty and and produce good wool and it was very different than other breeds that came before and he sent out and made it he found other breeds of sheep and he would breed them together in a barn where he had no windows because he didn't want anyone to see what his secret methods were and he became legendary for this he was once referred to as the man who invented sheep and you know future generations of natural ists were really intrigued by how he had done this and they were like well how did that work how did you take two different breeds cross them together and then produce a stable breed where the lambs inherit the same traits as their parents and one of the people who was really interesting this was Gregor Mendel and menville decided to try to look at these principles and in plants instead of animals and everyone learns in grade school or high school about how we crossed Pete plans together and so you know he's trying to understand how can you make a new stable cross and he was really intrigued that he could make these hybrids and then if he cross them together he would get these odd combinations so this is a classic example where if you have this pink flower pink hybrid flower and you cross them they look the same but their offspring have this 31 ratio of pink to white and so Mendel thought of this the way we call it today of dominance that there was some factor that was dominant and so that that would produce this pink color if you had one copy of it unfortunately Mendel then tried to repeat all of that with a different flower that had kind of weird genetics and didn't get the right results and so things sort of petered away Mendel didn't really know what to make of all the oldest because cell biology was not mature enough wasn't until 1900 really that Mendel's work was rediscovered by scientists who had been studying things like chromosomes and William Bateson was one of these people who was involved in rediscovering it was was so thrilled to see how Mendel he could he could think about Mendel's work as they're being factors on these chromosomes these factors would come to be known as genes and he declared the whole problem of heredity has undergone a complete revolution it says this in 1900 and that's when he coins that the phrase genetics the term genetics for this new science now this work had been done mainly with experiments on animals and on plants but there were plenty of people who believe that humans follow the same rules that you could do an experiment on humans but geneticists like Charles Davenport looked at genealogy at family histories as a way of possibly doing that Davenports the very complicated figure in the history of heredity II he rightly is condemned for a lot of things but we should also give him credit for the things that he recognized so just one example owning instance these this is a devastating disease causes really terrible neurological symptoms and is fatal and and Woody Guthrie is perhaps the most famous person who died of it Charles Davenport did a study in Long Island of families where people at hunting's disease and he showed that basically Runnings disease got passed down basically like pink color and people P plants it's like Mendelian seen it's a dominant trait in other words you inherit one copy of this Huntington's version of a gene you get Huntington's disease this was a big deal and it turned out to be right this is we know exactly where the variant is that causes Huntington's disease there's a gene called HTT and there's a section of it called you're the CAG repeat and if you have a certain number of repeats above I believe it's 37 you are going to get running into disease and so we know it down to this incredible specificity and we know that those repeats alter a protein called Huntington which is produced in the brain and so you know Davenport deserves credit for that now it's a century later we still don't have a cure for Huntington's disease based on that knowledge but at least if people want to be tested they can be tested however Davenport you know he really liked hit to make these trees and he would make them for all sorts of stuff so there was a very famous shipbuilding family called the hair shafts and so Davenport was convinced that he could trace their amazing skill by drawing a family tree and tracing boatbuilding and related talents like artistry or literature in the same way you know and he would present this as a serious science you know now we can't help but kind of look at it and laugh a bit at it unfortunately like he would also carry this on to to other traits where the outcome was far from funny quite quite horrific in some cases so one of the examples I talk about in my book which I think is really an important lesson for thinking about issues like heredity like about intelligence like about genetics has to do with this this man Henry Goddard and this school where he was the school psychologist the violent training school so dem port writes a letter to Goddard at the school wondering if they have done any family studies on their students these students are what we call quote unquote feeble-minded and that could refer to Down syndrome epilepsy or just a kid who was difficult in school it was a real grab bag but they would use the same label feeble-mindedness now Goddard had never heard of a really of genetics before this was kind of a revelation to him he had been just recently discovering intelligence testing in Europe and he was using that to to study the children at the violin training school and soon his testing was adopted by school systems throughout the country so IQ testing and standardized testing in general in the United States it's all it Goddard is the one who really pioneered it and now he discovers genetics and Davenport is wondering if people might inherit a gene for feeble-mindedness so he sends out people to go interview the families of students and also try to work back in their genealogy and he finds hundreds of examples that he's convinced show that that it is genetic to be feeble-minded and the one that he really singles out has to do with a girl named Emma Wolverton so on his intelligence test she tests a little bit below average and he comes up with a name for people like her so Emma Overton is the first and his genealogists come back and tell him that there's this comeback with this crazy story it turns out to be totally wrong but anyway he believed it that that one of her ancestors shown here in this tree Martin Kelly kak in the middle there that he slept with a nameless feeble-minded girl and then produced this long line of feeble-minded descendants when he taught me when he wrote about Emma Wolverton he referred to her by the name Deborah Kelly kak to protect her identity even though he would show photographs of her anyway then Martin Kelly kak marries the lawful wife and they produce lots of upstanding citizens for generations now you know if if for the scientists who study these sorts of things you might just be mind boggled that that anyone would take this seriously but Goddard certainly did he said the biologist could hardly plan and carry out a more rigid experiment and this is from a book he wrote called the calicut family and he thought that this data was among the most valuable that have ever been contributed to the study of human heredity so you know Goddard is really convinced by this and he's not the only one Goddard becomes incredibly famous for this there are lots of think pieces about this basically this becomes a a solution to the the crisis of poverty that is real that the United States is dealing with it's industrializing the cities are growing there's crime there are slums and now the middle class upper middle class upper class can look at at the downtrodden as just having bad genes you know that they know and but there's also the sort of sinful kind of echo like that so there you have see this headline for example how one sin perpetuates itself so that people who are feeble-minded and also criminal it's like this legacy that they can't escape Godard was invited to Ellis Island to the screen immigrants for these exact sort of traits this influenced the the immigration policy in the 1920s which basically viewed Italians Jews and Russians as mostly being feeble-minded so and and if that wasn't bad enough neo-nazi biologists they they took a lot from Americans like like like Goddard and so this is a still from a movie that you can actually find on YouTube does Arab German for heredity and you'll be shown in movie theaters a you know they're an educational film and so you know it's basically structured around a young woman a student who's asking an older man the scientist all these questions about heredity what is heredity then he talks about Mendel and he talks about flowers and he talks about horses and puppies and everything's fine until the subject turns to people and then they show this this is a german version of henry Goddard's tree and they're presenting this as proof that feeble-mindedness isn't is inherited and that if anybody is identified as being feeble-minded they need to be prevented from having children in the United States Henry Goddard and others pushed through sterilization laws so tens of thousands of people in the United States were sterilized thanks to the work of these scientists and then the Nazis took this to an even greater scale sterilizing many more people and then moving on to extermination this isn't like a this isn't like there's some sort of similarity between America and eugenicist and and Nazi biologists the connections are clear you can see them in things like this and we need to really remember the dangers of this especially because you know one thing that's really striking is that is one things really striking about this is that all of this happened when people didn't really know very much at all about heredity so they knew my genes but didn't know what genes were made of if you had told Bateson huh did genes are DNA he would look at you kind of funny because they just wouldn't really understand quite what that meant and the level of detail that we do now Bateson thought that you know that there was a revolution in 1900 I would argue is about maybe a hundred years off it's when we're able to sequence DNA on a large scale like being able to do the first human genome that things really change now in 2000 that first team in genome it cost about three billion dollars and so it wasn't something that you know was going to be a consumer product obviously but the cost of sequencing DNA either little bits of it or the whole genome if you want to be more ambitious with it has been falling dramatically this is a chart from the National Institutes of Health showing how it has fallen this is logarithmic you have to remember so that now we're down to under a thousand dollars and people are expecting another fall pretty soon we're gonna get be getting down to just a few hundred dollars so so people are are then able to get tests from places like 23andme through genotyping or you look at you know maybe one in a thousand genetic letters it's a little harder to get your whole genome and but I got really I got had an opportunity to get my genome sequenced and by hook and by crook I was actually able to get all the raw data and so in part of my book I talk about you know trying to look at my genome to understand things that I have that I have inherited and to understand you know understand my my ancestry through the this gigantic spreadsheet this is my brother Ben and he had gotten his DNA sequenced through think ancestry but genotyping but that was enough that we could compare our DNA through with the help of Yanni bear-like and others at DNA eland and these red parts are the parts of our chromosomes that are identical and so you know that's a lot of identical DNA and that you don't get that unless you're really closely related so if we get any doubt we are brothers which is good to know but in addition to that I can look at other relatives this is not my brother but it's a pretty good likeness of an ancestor a Neanderthal on the Anna trawls are the fossil record from about 200,000 years ago to 40,000 years ago and it turns out that to larger or smaller extent pretty much everybody on earth has some internal DNA mmm Europeans and Asian's and and people and the Americas have large amounts people in Africa have a smaller amount the reason for all this is that it is that Neanderthals and and the ancestors of modern humans shared the world at the same time and they came into contact our species evolved in Africa and then moved out expand it out and encountered other kinds of humans and interbred with them and these arrows are just a few of the exchanges of genes that happened when these different kinds of humans interbred so you know some of them with some of these services you can find out you know do I you know what's my percentage of Neanderthal DNA am i 1% to my 2% I was actually just curious well what what are the genes and and so I got some help from Joshua Iggy and Selena vada Hill at Princeton they took a look at that that genome I showed you and they gave me a list a list of Neanderthal genes which is pretty amazing this is just started it's hundreds of genes long and of course you know I look at a list like that and I'm like wow well what you know what's fgr what does it mean that I've FDR a lot of the in a lot of these cases we don't actually know what what these genes do and even when we know what they do we're not really sure what they're up to and it's possible that Neanderthal genes are important to our immune system maybe they influence our brain but very preliminary studies very small studies on those on those findings just this past week there was a really big study where scientists looked at 27,000 people in Iceland and looked at all of their Neanderthal DNA and tried to see whether there was any strong connection to really any trade at all that they could measure and they pretty much the answer was no you know if it was slight if at all now that might be surprising to you like you might think like oh like if I have a Neanderthal gene I must be Neanderthal and some profound way but the fact is that for a lot of our traits that's just not how things work things you know Mendel open the door to understanding heredity in terms of genes but if you just think of a trait hat being controlled by a single gene that's gonna lead you awry when my favorite examples is height and I talk about height in the book scientists have long been fascinated by height mostly they tended to look at the the outliers so I was that people are really tall or really short but you know there's a whole range of Heights in between and height is what scientists call very heritable in other words short parents tend to have short kids and taller parents tend to have tall kids so there's something going on with genes in my book I talk about Joe Hirschorn and he's a pediatric endocrinologist and me parents would come in with kids who were you know in the short side and they were concerned about this and he'd say well your kids fine your kids healthy this is not a medical condition and but they would want to know why their kid was short and he would look at the parents and to be an awkward silence he'd say well you're not that tall yourself honestly and they would get into discussions about genes and they would ask what these genes were and he didn't know and that kind of launched him on a career of trying to find the genes for height as a way of understanding how genes influence our biology took him a long time and had to look at almost 5000 people before he found one gene and this gene that turns out I had one variant of it that basically is the equivalent of me putting on a very thin pair of socks so it makes me a little bit taller and you know a fair number of people have this variant three years later they expanded 183 thousand people and found 180 different genes that had an influence but all those other genes have a smaller influence on height than the first one 2014 almost 700 genes down and then just recently in 2018 a couple years ago over 3,000 variants and that was based on almost 700,000 people they're gonna be going on to looking at much larger groups we probably should expect thousands of more sites around the genome that have a influence a faint influence on height and that's just you know height that's because I kind of reflects a lot of things that happen in our bodies it has to do with how our cells divide how our bones length and our muscles keep up with it when we stop growing what signals cue that so height is something you can measure very simply just with a little tape measure like the man on the chair but but it turns out to be incredibly complex and you know we also need to just remember that um you know just because a trait is influenced by genes in other words that it's heritable doesn't mean that it is by the genes and that doesn't mean that we should always just resort to extreme based explanation because we'll get in trouble up again so here we have some data from Canada and Barbados of the average height of women so there's a pretty substantial difference here about five point five centimeters and so you might say like oh well limiting Canada must have a certain set of genes that makes them tall taller than women in Barbados catch is that this data is old it's from 1896 maybe jump forward a hundred years both countries have taller women on average and the women in Barbados are now taller than the women from Canada and the reason for that is that worldwide quality of food is improved and medicine has improved a lot of things that improved these are social changes they're not genetic changes so II you know you can still you know make some predictions about people's relative height looking at their genes but the whole world is taller now on average and it doesn't have to do with with with a genetic or entity you think of as a cultural heredity that is influencing it so just to wrap up and then I'm happy to take questions these are these are a few of the lessons I think are really important to to to think about now that we're gaining this power to manipulate DNA and to even be able to steer the future of heredity it is possible to to alter genes in a fertilized human egg and you know when you do that the embryo that develops it's going to have all the all the cells in that embryo going to have that change including eggs or sperm and and so in other words that that if that bit embryo becomes a person then that person is maybe able to pass on those changes to future generations this has been a thought experiment since the 60s and I write about in my book and then in 2018 it became a reality of sorts when hey jianchi I'm mispronouncing his name I apologize he he announced that he had altered the DNA of some human embryos and there were at least two babies that were born with these changes he claimed that he was doing this to make these children resistant to HIV but as far as scientists can tell he was quite reckless and probably introduced mutations that were not what he had even intended he was he was he was charged by the Chinese government and you know you might think well that's the end of it we'll never see that again and obviously in the world of Koba 19 we're quite distracted from these sorts of long-term issues but we need to bear in mind that this is not going away in 2019 a Russian biologist Dennis HOF said that he was you know exploring the possibility of doing exactly what had happened in China where maybe he was starting to canvass parents who had a hereditary form of deafness saying do you want your child to have altered genes so that the child not be deaf this raises a lot of complicated issues is do we consider deafness a disability or you know have you talked to the deaf people in the deaf culture who have their own language and so on they don't see it like that at all are we going to make shortness a pathology what are we going to decide is disease and what are going to decide is health now you might argue that you know maybe we should be using CRISPR to basically sort of protect future generations from diseases like Alzheimer's I don't think anyone would would argue like somehow that Alzheimer's is not a disease not a pathology it's devastating it causes death it causes dementia and there are we're learning more and more about variants that may protect from from Alzheimer's disease one of them is a variant of a gene called Clotho and this is just one of many recent papers that have come out looking at how it can protect from Alzheimer's disease but there is something else about it too which is that it it's also there's some experiments that suggest that it can actually enhance learning and memory when you're younger so you know you you you you may not be able to have that sort of protective sort of medical treatment without this more problematic enhancement do we do we feel okay with people being enhanced in this room this way if people say well only the rich people get it would you feel okay if it was just available to everyone you know did I think some people would still feel uncomfortable about it and just starting to wrap up now I mean I would I would say as we wrestle with these questions and we will be wrestling with these questions for decades to come I you know we should we should think about history we should think about someone like Emma Wharton sorry Emma Wolverton you know she was examined by the leading scientists of her day and based on you know the the new science of heredity that everyone thought they understood she was judged unfit for ordinary life and that it would be a terrible thing for her to have children after she grew too old to be at the violent training school she was moved across the street to an institution for feeble-minded women where she spent her entire life she was not feeble-minded she did all sorts of things she she produced plays she she made clothes she played the cornet she taught herself how to make cabinets and wooden boxes she wasn't a really remarkable person but she herself became convinced that she was not fit for society in her sixties she was offered the opportunity to leave her institution and she said no I guess it's just not for people like me uh-huh and that is that was one of the the biggest tragedies of how science can be misused of our century that kind of treatment of people so as we as we go forward into into this strange new future of heredity I hope we all can keep Emma Wolverton in our thoughts so thank you very much there's I talk about this and a lot more in my book so if you're curious you can check that out and I'll be happy to take questions hey well thank you very much and it was a fantastic talk and anybody there hasn't read the book should definitely head out and get it get even more interesting information we have one question on the on from the web that's kind of release the last part of your air talk but which is what are the current watchdog procedures regarding human genetic they say testing but specifically referencing the recent Chinese activities with CRISPR and so how is it being regulated these days it's a real patchwork of regulation and it's you know there you know in the United States it's not that research along those lines is not permitted but you know there's no saying that people might not go to another country to to get these kinds of opportunities you know the National Academy of Sciences is actually put produced a number of important reports on this and as you know I would argue has left open the door to the possibility of germline intervention in certain cases where there's an inherited disease and there's really no other way of dealing with it in order for parents to have children but I think it would be very rare cases where some other approach couldn't be used instead you know I mean the fact is that at fertility clinics for example there are parents who have conditions like onions disease where they are picking embryos in order to avoid their children inheriting their disease so they may not be rewriting the DNA but they are intervening and that that is a big deal there's a related question which is about any research into epigenetic editing to alter this type of disease yeah you know B I have a chapter on epigenetics and and I it's an amazing fascinating area you know I was trying to convey with height just how complex genetics can be the genetic inheritance is really it's it's a lot more complicated than we may have given it credit for and that's stuff that we have scientists have been studying for over a century epigenetics is even murkier I would argue so epigenetics is basically has to do with the molecules that that control which genes get to be used and it's that's very important for us during our lives and it's what you know for example you know why your cells in your eye are different than the cells that make hair even though they all have the same genes now the question is like are any of those molecules able to be passed down to the next generation that's a huge area of debate and research and there are some great examples but they have to do for example with plants or tiny little round worms the evidence from humans is much less and much more highly debated but obviously because it's humans people want to know about it so I don't think answers are going to come very quickly because when you get to mammals this kind of research on epigenetics and and the inheritance of epigenetics is really hard to do it's really hard to reject other interpretations of the patterns we see so I wouldn't hold your breath for that side of things but it is fascinating okay I'd like to know what Karl thinks of genome-wide Association studies or gos studies and that look at poverty sex preferences a number of different kinds of things in jiwa studies yeah so so genome-wide Association studies they're kind of like what I was describing with hike basically like you you you you get a lot of people and you look at it a trait like height for example and so some people looking to be taller than average some people shorter than average and then you look at variants that they have in their genome and you say are there any variants that are unusually common in people who are shorter than average or taller and taller than average and you can tease them out and so you know we now have identified thousands of genes that are in influence height now the design in itself is interesting but you know if you are expecting some sort of easy answer to what height is that can be a little frustrating and you know there are complex traits like you know diabetes is a complex disease and there are genes that influence your risk of diabetes scientists found lots of genes associated with diabetes that has not directly led to you know the elimination of diabetes and so you know there were a lot of promises made in the 1990s at sequencing the genome would lead to lots of cures some those those treatments are coming but they're coming pretty slowly and for the most common for the most for the most common complex traits and diseases it's that we just keep discovering that biology is you know ever more complicated so so it's and and once we get into things like intelligence which I write about in the book or for example educational attainment then we get into even murkier territory because what is what is that connection between a little variant and you know on average people having an intelligence then IQ score like a quarter of a point higher than average what does that mean what is the connection there and how does the environment influence that or work against that or enhance that okay well thank you very much and I think we've run out of time so again we very much appreciate your time thank you thank you thank you it's been a pleasure oh thanks

Channel: National Academy of Sciences

Views: 603

Rating: 5 out of 5

Keywords: DNA, genetics, genetic, gene, heredity, science, National Academies of Science, Carl Zimmer, She Has Her Mother’s Laugh

Id: BouH1v0BaV4

Length: 45min 9sec (2709 seconds)

Published: Mon May 11 2020