Rethink everything we know about genes and identity politics | Adam Rutherford | TEDxGlasgow

[Music] hi so genetics DNA ancestry these are the things that are just everywhere these days which is great for me because I am geneticist but I think and I'm going to argue here that we've been talking about inheritance and ancestry and genetics wrong for several thousand years and now in the 21st century when we know tons about genetics we are still getting it wrong genetics is merely the study of families sex ancestry and history and the families that we know most about from history our royal families so I'm gonna bookend this talk with two European Kings my first king is charles ii of spain now charles ii spain was the last ruling member of the Habsburg dynasty the most powerful family royal family that Europe has possibly ever seen but he died two weeks short of his 38th birthday in on the 1st of November at 1700 we all know about the Habsburgs and we all know how they provided every single Holy Roman Emperor for 200 years but it all came to a crashing end here because Charles didn't leave a son or an heir he lived an extremely troubled life what followed his death was the Spanish war of succession where the biggest families in Europe fought and scrambled for the spoils of the collapsed Empire but during his life he was profoundly disabled he didn't learn to walk until he was four he didn't learn to talk until he was eight and when he did the permanently swollen tongue in his mouth rendered his words dribbling and his speech garbled so his courtiers the people of Spain gave him a nickname which was Carlos head chief Ardo the hexed or the bewitched now we all know about the Habsburgs we the thing that people mostly remember about the Habsburg dynasty is that they had this very striking physical characteristic in their faces hams burger lip or house Berg jaw and here's a selection of them through time top left is Charles two seconds his father's below him I don't really know what's going on with his this guy here and the chap bottom right is actually his aunt and we laugh about how unattractive they are with this ridiculous chin the habsburg lip but actually they regarded it as a kind of a badge it was emblematic for them of their divine power and they tried their best to keep this emblem to keep this physical characteristic in their family for as long as they possibly could now the reason that Charles lived such a bewitched life is because 150 years before he was born this family stopped out breeding so I want you to think in your head of a standard family tree your family tree so you at the bottom with two parents and four grandparents and eight great-grandparents and so on back seven generations if you go seven generations back you should have more than 250 people in your family tree maybe a few less than that I'm from Suffolk so I can say that with impunity alright so you got that family tree in your head yes now this is the family tree of Charles a second yeah right there are 29 people on this family tree so he's almost an order of magnitude short of the required number of people that you should have going seven generations back now what that means is there are some fairly distasteful relationships going on here mostly between uncles and nieces but fundamentally what it means is that multiple positions on this family tree are occupied by the same person I can give you dozens of examples but I just focus on one margarita of Austria is his grandmother on that side and his great-grandmother on that side she's also his great-aunt at the same time now we refer to this as being sub-optimal if we then scoot up to the top of this family tree it's all seeded with the pairing of Philip of Castile and yoanna of Castile Philip the handsome fell at the first now yoanna had a nickname too she was known as Yohan a la loca the mad or the insane so if we go back to the family tree now we can see that there are in fact nine different routes you can get from Charles to johanna la loca which means that she occupies nine different positions which should have nine different women in his family tree on three different generations again this is what we refer to as sub-optimal but it is it's an interesting irony this because that chin the idea that they have a characteristic an essential characteristic that they could pass from generation to generation and this would be emblematic of some traits in their family that they wanted to hold on to the tighter they grip tips the irony was that the more they risk losing power forever which is what happened when Charles failed to produce a son or an heir now this is an idea which actually predates this by a couple of thousand years so this is a this is a section from the Jewish holy book the Talmud written in the 3rd century BC and this section describes how there's a small proportion of Jewish boys who are not circumcised they are allowed to be excused from circumcision if two or three of their brothers in a particular pattern have died have bled to death having been circumcised at Birth and what we now think is this is a this is a description of the blood clotting disorder hemophilia so this is written in the 3rd century BC but this again is the ideas prefiguring the idea of the gene that there is a unit a thing which is inherited from generation to generation and can be passed on now I'm just gonna skip through 2,000 years worth of scientific history now and take you forward to Gregor Mendel everyone knows Mendel we learn about it at school we know how that he was a Moravian monk actually was just a scientist who happened to be a monk and his experiments with peas he bred peas together and with he worked out the rules of inheritance he worked out that there were particular patterns to the way characteristics and passed from generation to generation units of inheritance what we now call genes and hemophilia what I was just talking about from from the Talmud this is inherited in a Mendelian way right so we got this rule we've got Mendelian rules got Mendelian inheritance this is a core part of genetics a core part of biology and we like rules in science the trouble is that biology is messy and our rules are often fragile and frequently they are broken so I'm going to skip forward another century now and take us to the human genome project one of the great scientific endeavors of all time in that we sequenced the genome of humans of us we read out the entire genetic code of people what an amazing accomplishment that was amongst the discoveries within that we counted accounted for the 20,000 genes that each of us has now 20,000 is an interesting number because it's fewer genes than rice that's a water flea Daphnia that's a roundworm and bananas now we kind of tend to think that we're a bit more sophisticated than bananas most of us and so we then began to think well actually maybe your model of genetics isn't it's a bit more complicated than just that simple Mendelian rules we have essential units of inheritance genes for essential characteristics and actually what we began to discover is that most traits most characteristics are very complex coordinated interaction between dozens or hundreds of genes and they all interact with the environment and that is how DNA becomes a lived life but still within culture we still hang on to this sort of ancient idea that there is a gene for things that there are are specific units which we pass on from family to family and that is your fate to have hemophilia or perhaps Berg chin and it is true that if you have a mutation in the Huntington's gene then you will get Huntington's disease which is awful or if you have a mutation in two copies of the CFTR gene then you will have cystic fibrosis but for the most part it turned out that genetics like people was much more complex than we had anticipated but I think this hasn't filtered down into the public discourse about what is important when we talk about genetics which is just how families actually work how inheritance is passed from generation to generation now I said at the beginning genetics is everywhere well that is true and we got really good at sequencing genomes and there are hundreds of thousands of individual genomes now available to scientists all around the world mostly for free that they can mine and study to try and understand the things that they are interested in whether their diseases or complex traits or ancestry in our history but the truth is that that number is absolutely dwarfed by the number of human genomes that are owned by commercial companies that you have paid for to in exchange for mostly for information about your ancestry but also stuff like well you can get tests to supposedly genetically hone what wine you might be interested in or what face cream would suit you best or what sports your children should play now I this is a kind of wild frontier of some seriously dubious science I think that most punters actually realize this but it all plays into that that narrative that genes are faint that there are individual units of inheritance which will make you good at this sport and not at this sports all that well you know this is the wine that you prefer because it's in my genes now when it comes to human evolution and ancestry genetics can be really really informative but ancestry is complex and it is a little bit messy so many of you will have done tests for you paid some money spent the tube you get a few weeks later you get a sort of report on where your genes are found in the rest of the earth it's complicated and it's a kind of an interesting sort of fun slightly trivial thing 23andme is the biggest company this is an advert that they put out last week suggesting that some the ultimate football fans supports the teams that they are most closely genetically associated with I don't know about that now the thing is that you know we can tell you lots of things about ancestry about human evolution from from our genomes lots of those things are kind of high sometimes counterintuitive some of them change the cultural narratives that we have it's a brave possibly foolhardy man who stands in front of 2,000 glass regions and tells them there's no such thing as Celts what I mean by that is that Celtic people are not a genetically distinct group that is a cultural grouping so appreciate if I could leave here alive and I get emails every single week from people either saying or asking whether they're descended from Vikings because let's face it Vikings are really cool and everyone should be much more like Thor now like I said it's trivial it's fun but there's a much more pernicious there's a much darker side to this now I do something which I really really thoroughly recommend you never ever do because it is not good fuel for your mental health do not do this at home I haunt the web sites and forums of white supremacists and neo-nazis and that got a laugh that was that's interesting so that's how it's gonna be in Glasgow and I'm looking for specific conversations about people fascists racists using these new genetic ancestry kits in order to establish their own ethnic purity their words not mine and therefore their racial superiority now this is this is bad news but more importantly it's scientifically specious this is using science or misusing science in order to justify racism and I'm not cool with that so let me tell you how ancestry really works now remember that family tree that's you are thinking about at the beginning this is this is a standard family tree that we use in genetics so there you are at the bottom two parents four grandparents a great-grandparents and so on and so on 250 people in there now and standard in genetics is to think about 25 years as a generational time so you get four generations on average per century and this is seven generations so this is one person's ancestors going back to the middle of the nineteenth century so it's about 250 people for one person going back to the middle of 19th century which means that for people it's going to be a thousand people a thousand ancestors in the middle of the nineteenth century and so a hundred people say the front two rows of the auditorium here that is going to be nine hundred thousand people in your ancestry of a hundred people going back to the middle of the nineteenth century now we can't keep doing this because if we continuing to continue to double the number of ancestors that you have every generation back through the past by the time you get to the 10th century the number of ancestors that one person will have is going to be one trillion salla trillion it's a trillion now that is about a thousand times more than the number of humans that have ever existed so that can't be right we know exactly what's going on here it's a little bit like the Habsburgs but not in a really dangerous way actually as you go back through time your family trees begin to collapse in on themselves and multiple positions on your family tree are occupied by the same person it is a form of inbreeding but actually we refer to it as coalescence now ultimately we know this of course because if you look at a family tree of first cousins they have a shared ancestor in a grandparent and all the people above the grandparents are the same right so their shared ancestry their and so what that means is you can you can see how your the branches of your family tree begin to become entwined with each other the further you go back to history we have to deal with the fact that there are more people alive today than at any point in history but historically you should have more ancestors than at any point in time so you clash those two numbers together now eventually what falls out of this initially about 15 years ago worked out in mathematics and more recently using genetics by teams over in America Graham coupe is that you come up with a concept which is known as the ISO point now this is quite a tricky concept to get your head around but what it is is the time when all branches of all family trees cross through all individuals alive at that time okay or another way to think about it is at the ISO point everyone alive who has descendants alive today is the ancestor of everyone alive today does that make sense just not okay when the ISO point for Europe was calculated a few years ago it came out as the 10th century Wow a thousand years ago everyone in Europe who has children who has descendants who are alive today they were the ancestors of literally every European alive today all branches of all family trees across through all individuals only a thousand years ago it shows how profoundly closely related we all are who do we know who has descendents who are alive today who was alive in the 10th century well mercifully thankfully not Richard Branson or Christopher Lee but both of them have done their family trees and demonstrated that they are descended 40 generations from Emperor Charlemagne the first Holy Roman Emperor now the fact that he was alive in the ninth century before the ISO point means that yes Richard Branson and Christopher Lee are descended directly from Charlemagne but that also means that everyone is literally all Europeans are directly descended from Charlemagne remember I talked about the Vikings and minutes ago the Vikings came before Charlemagne which means that literally all white people on earth are descended from Vikings if you want to pay a hundred quid and spit in a tube to have some guy in a white coat tell you that fill your boots I'm telling you this for free now look what does this mean I started with one King and I ended in with another in order to talk about how we talk about inheritance and how we've got it wrong over the years and how we have to think more carefully about what genetics and ancestry actually means because you know it turns out that ancestry is messy biology is complex genetics is super complex people are horny and if we really want to understand ourselves and our families and our history then we need to embrace that complexity thank you very much you

Channel: TEDx Talks

Views: 21,452

Keywords: TEDxTalks, English, Science (hard), Genetics, Science

Id: f55-ltaieV0

Length: 17min 56sec (1076 seconds)

Published: Wed Jun 13 2018