In Our Time - Genetic Determinism

Episode Date: September 23, 1999

Melvyn Bragg and guests discuss the theory of Genetic Determinism. In the middle of the last century two men - Gregor Mendel, an Austrian monk, and Charles Darwin, an English naturalist, established the central theories of modern biology and changed the world forever. Darwin’s On the Origin of Species has been described as the book of the Millennium, “the only best-seller to change man’s conception of himself”. Through the rediscovery of Mendel’s work in the early decades of our century, evolutionary theory was transformed by the emergence of genetics as a science. Crick and Watson found DNA at Cambridge and announced that they had discovered the secret of life in a local pub, and the rest has been the most compulsive element in the intellectual history of the twentieth century. It seems as if almost every week we read about another gene which claims to determine our fate - whether it governs our intelligence, personality or sexual orientation. Many rail against what they see as “genetic determinism” - the idea that genes are the destiny we can do nothing about. Others willingly blame their anti-social behaviour on “criminal genes” - thus absolving themselves of any responsibility. Genetics may be all about inheritance but is inheritance all about the genes? With Steve Jones, Professor of Genetics, University College, London and author of Almost Like a Whale: The Origin of Species Updated; Matt Ridley, science journalist, chairman of the International Centre for Life and author of Genome: The autobiography of a species in 23 chapters.

This BBC podcast is supported by ads outside the UK. Thanks for downloading the In Our Time podcast. For more details about In Our Time and for our terms of use, please go to BBC.co.com.uk forward slash radio 4. I hope you enjoy the programme. Hello, in the middle of the last century, two men Gregor Mendel and Austrian monk and Charles Darwin, an English naturalist,

established the central theories of modern biology and changed the way the world thinks. Darwin's On the Origin of Species has been described as the Book of the Millennium, quote, the only bestseller to change man's conception of himself, unquote. Through the rediscovery of Mendel's work in the early decades of our century, evolutionary theory was transformed by the emergence of genetics as a science. It seems as if almost every week we read about another gene which claims to determine our fate, whether it governs our intelligence, personality, or sexual orientation.

Some worry about genetic determinism. Others are eager to blame their antisocial behavior on criminal genes, thus absolving themselves of any responsibility. Genetics may be all about inheritance, but is inheritance all about genes? Two scientists trying to make sense of this tangled history of Steve Jones, Professor of Genetics at University College London, and Dr Matt Ridley, science, journalist and chairman of the International Centre for Life. Steve Jones is the author of Almost Like a Whale,

which updates Darwin's on the origin of species. It's been widely, and I think rightly acclaimed, as a remarkable, bold and very readable book. Matt Ridley has written another captivating book. It is on the special nature of human beings on the genome, which is the complete set of genes contained in a human beings, 23 pairs of chromosomes. His book is called genome, the autobiography of a species in 23 chapters.

Steve Jones, you call the logic of the origin of the species, quote, as powerful today as when it was written. So what moved you to rewrite it? The feeling that really we have to keep explaining why we believe, what we believe, Everybody believes, for example, now, I think, almost everybody believes that the sun does not go around the earth, things are the other way around. We all know that, but if you're to ask people why we know that, they might begin to stutter a bit.

We can certainly talk about satellites and so on, but they probably wouldn't know Galileo's explanation, which is very subtle and how to do with the movement of wandering stars and fixed stars. And evolution is much the same. We all believe, or most of us believe, perhaps, that we evolved. But if you're pushed into a corner and said, Why do you believe that? It might be rather hard to do.

So the thing about the origin of species, it is a remarkable work. Its structure is fantastically powerful. Darwin called it one long argument, and it's a wonderful book. But, of course, he was writing in 1859 before modern biology began. So what I've tried to do, perhaps rather too boldly,

is to use that structure, that framework as a kind of scaffolding around which to build a modern building. Why do you think that, on the origin of species has remained so intact when roughly similarly influential books around the same time. And in the first half of the century, like Das Capital and Freud's interpretation of dreams, have been shot at and often shot down very much. I think that's a simple, one of the, it's science.

And in science, things are, generally speaking, if they're true, they're established, they tend to stay upright. That doesn't always happen. It didn't happen to physics. And it may well be that there'll be a new quantum theory of evolution, which we can't even contemplate yet, but we haven't got there yet. And it's so clearly correct, and it so clearly explains things that were previously inexplicable, that it stood up remarkably well.

And the thing which saddens me slightly about the people who attack the origin, particularly from the creationist end, is they make such a bad job of it. If they could come up with some convincing facts that it doesn't explain, then I'd listen to them, but instead they just waffle. What would have surprised Darwin about what you've written? I think genetics more than anything else it would have great be cleared his mind too I mean Darwin was you know I keep saying this in a boring fashion

but it's true I mean Darwin was the most extraordinary genius and he was the best kind of genius he was that very rare thing which is a modest scientist those two things don't often go together it's a bit like Scottish amicable and so on the contradiction in terms he immediately realised when somebody pointed out to him that his theory was flawed

because his theory of inheritance which is roughly speaking the mixing of the bloods of dilution. If that happened, any advantageous character would be diluted out so evolution couldn't work. And Darwin was honest and he saw that straight away and he spent really much of the rest of his life trying to get round that problem. He didn't know, of course, but the problem had been solved by Gregor Mendel about whom Darwin knew nothing. Matt Ridley, when you came to write your book, how influential was Darwin on you?

and how is that absorbed into your book about the human genome? Well, I think that the human genome does, in a way, vindicate an awful lot of what Darwin said. And the history of species, the history of how they diverge, the history of our own species. When is it vindicated? Could you just explain it? Well, if you take, for example, the origin of life or something like that, we can now trace back to, we can find that there's a universal genetic code, all living organisms from beech trees to bacteria use the same genetic code. They use the same material DNA and they use the same way of interpreting it.

And that implies a common origin. And then if you look at particular genes themselves, you can find a bunch of genes called the hoax genes in humans on chromosome 12, which determine the body pattern of the embryo. They lay out which is the head and which is the tail, as it were. And exactly the same genes are in fruit flies, so much so that if you take a gene out of a human, put it into a fruit fly, it performs the same function.

The fruit-fly mechanism can recognize it. And that implies that the common ancestor of humans and fruit flies, which we know lived more than 600 million years ago, had this mechanism in it. Now, you know, that's the kind of thing where... The kind of thing which the fossils can't tell you, but the genes can add to the story. So is that why you...

That's why you called your book an autobiography, obviously, or subtitle, the autobiography. Can you just explain that a bit further, why these 23 chromosomes give us the autobiography of the... of the human right? Well, it's a slight of hand, perhaps, because the way I've written the book, I start with the origin of life and find a gene on chromosome one that is very ancient

and that we share in common with all of other creatures, and I gradually work my way up to much more human issues at the end. But that doesn't imply that chromosome one came first or anything like that. I mean, in chromosome two, I talk about the evolution of humans from apes, and the reason for that is that chromosome two is actually two ape chromosomes that fused. In all the other apes, there are 24 pairs of chromosomes, not 23, and the difference being that two of them fused when we came along. So I say rather facetiously that on the place where they fused, that must be where the human soul has the gene, which of course I don't mean literally, but it's an excuse to talk about that thing.

The autobiography point is a, again, it's a bit of a conceit because what I'm saying, is that the genes record everything that's happened, both to our species and to the species that went before them. And so in a sense, if you can read it, as we now can for the first time, you can learn a lot about what happened to us in our formative years several hundred million years ago. Steve Jones, you admire Darwin the more that his theory and his thesis holds strongly despite the fact that he knew nothing about genetic?

Yes, I think so. I mean, one as a biologist is more or less forced to chant the Darwin mantra from the cradle onwards. I always believed Darwin to be a genius, although I won't admit when I first read the original species, it wasn't as young as I ought to have been. But now, rather like the theory of evolution itself,

I know he was a genius. I mean, you can see the strength of his argument, and you can see what I like most about him was his willingness to see the weakness, his own weaknesses. Half the book is pointing at the possible weaknesses in his case, and he sees them all. Can I ask you just, I know it's a huge question,

but can I ask you, why do you think that Darwinian has spread into so many other areas of the culture and that people use Darwin so often. So not all that loosely as well. They try to follow his ideas. He's now the way we think about many things, isn't he? I think in part, because it's a tremendously simple idea,

all it is, as Matt said, is its descent with modification. Things are passed on from generation to generation, and they change as they do. Now, that seems a rather banal statement, but to the 19th century it was astonishing. there is a fatal tendency to use Darwinism where it really could not be used. Darwin himself was very reluctant to use his theory

to explain human society, let's say. And there's a tendency in Darwin for evolution to be rather like a sofa. It moulds itself to the buttocks of the last person to sit on it. So you find, for example, Karl Marx was tremendously keen on Darwinism as the rationale for communism. Whereas Herbert Spencer, who invented that slightly unfortunate phrase the survival of the fittest and is buried just across, as you know, in Hygid Cemetery

from Karl Marx. He was a great proponent to the idea that Darwinism made capitalism okay. Sidney Webb thought Darwinism made liberalism okay. So any one of the three-party conferences going on now, you could have a Darwinist on the platform and if you feel perfectly at home. And under those circumstances, of course, it really has no use at all because it's simply being used like religion to explain any conceivable pattern of human behavior or society. and that's just empty. And a lot of people would say that religion isn't empty, and clearly you believe that Darwin isn't empty.

So although it's plastic and elastic, there's still something harmed at the core of it, obviously. Oh, definitely, I mean, most definitely. As Matt's book makes very clear, Darwin would have loved to have read genome because it would have reminded him very strongly of those terribly terribly boring books of comparative anatomy that 19th century biologists used to read,

the map of the cat or the insect. All that molecular biology is, is comparative anatomy plus an enormous research grant. Let's go into this human genome project. Now, you say in your book, Much, in a few short years we'll have moved from, quoting you, from knowing almost nothing about our genes to knowing everything. I genuinely believe that we're living through the greatest intellectual moment in history,

full stop, bar non, end quote. That's a big claim, but just can you briefly tell us where we are with the human genome, genome project, genome project, and why you think it's so fantastic? Well, I think the story starts 50 years ago, when we didn't know what genes were. We knew they existed and we knew they influenced inheritance. We had no idea how they worked.

And then came the discovery that they were digital codes. They were essentially text. They were like books. They were written in linear digital codes and they were instruction manuals. And that really was what Watson and Crick discovered in 1953. And in the 50 years since then, we've understood a lot about how they work. But we are now for the very first time in a position, when I say we, I don't mean myself. I mean the science in general is the very first time in a position to read the complete.

instruction manual for human beings. It's a very long book. It's 800 times as long as the Bible, and we've got 100 million, million copies of it inside ourselves as we sit here. And yet, this winter, we've read about 20 to 25% of it, a lot of it in this country at the Sanger Center.

And this winter, that will go from 25% to about 95%. By February or March next year, they're predicting that they will have the whole thing deciphered and worked out. Now, it's then decades before we understand everything that's in it, but we've got it to look at. We've got it to explore. So what have we got then, Steve Jones, with this human genome project? What have we got? Well, we've got a banal image, a manual. But my fear is that the manual may be written in Chinese.

We have something, which is a great string of the four letters, A, G, C and T. It's a long, long way from having that to knowing how it works. I mean, I remind myself that the structure of the heart, the human heart, was discovered by the salius in the 15th century, and the first heart transplant was in the 1960s. I'm not saying there's going to be that much of a gap between seeing what the heart of ourselves looks like and not only understanding how it works, but doing something about it, but the gap is going to be longer than most people think.

Do you think that for Darwin, Matt Reddy, natural selection acted solely on the individual. Do you think that translated to the genetic level, we're talking about the selfish gene again? Well, I do think that that's, and I may not be quite at one with Steve here, I do think that that's one of the big things that's happened in the past century is that the transformation of evolution from essentially a theory about individual struggle to essentially a theory about genetic struggle.

because, and in fact the structure of the human genome as we look at it does bear this out to a remarkable degree, particularly the huge quantities of what's now known as selfish DNA that's in there or junk DNA, stuff that's in there because it's good at being in there, it's good at getting itself copied, it serves no purpose for the individual, it's simply there because it's good for itself, as it were, it's dead retroviruses and things like that. And essentially what the theory of the selfish gene does is, say that quite often what counts is the survival of genes, that individuals often do things that are bad for themselves but good for their genes.

And this enables them, this explains the problem which Darwin wrestled with, of altruism, of why people are nice to each other, because if it's a struggle between individuals, then they shouldn't be nice to each other. So, but if, for example, if you take the example of human beings having children, people have children essentially because they're sort of instructed by their genes to want to have children. They enjoy the experience because they're built in with instincts to enjoy the experience. In fact, it's a pretty thankless task for the individual,

but it serves the purposes of the genes. What's your take on that? Well, I think that's obviously true in some general sense. And Darwin, again, with his great genius, saw a huge problem in his theory, was the evolution of sterile insects. How could evolution possibly make something that's sterile? and the answer was he saw on once that it's because the sterile

helped their relatives who now we'd say have the same genes to make more copies of those genes. Now in some sense is that true. That's true. The genes are in control. But one has to be rather careful to understand how little that means. I mean, I got here this morning. I could say my legs are in control.

My legs dragged me out of bed down to the taxi that arrived on time and into broadcasting a house. But that isn't actually saying very much interesting at all. people overuse the power of the genes as an alibi I'm often reminded of the Flanders and Swan song about cannibalism you can't eat people

and there's this very funny song about a young lad arguing with his father about the morals of eating people and his father comes out with the perfect biological answer he says if God hadn't meant us to eat people he wouldn't have made us of meat and that makes perfect sense but he's actually rather empty and it's the same argument is used

by those who utilize DNA as the universal excuse for human behavior. Sure, we're made of DNA, but my answer is so what? And your answer to that, Matt Rutherland? Well, I disagree there. I think that it is absolutely central to understand the way in which genes play a sort of autonomous is the wrong word,

but that evolution is often happening at the level of the gene rather than at the level of the individual. and the difference between evolutionary theory in sort of Darwin's time was that he didn't really appreciate that. For example nowadays, a lot of nearly all research that goes on in animal behaviour into things like sexual selection, sperm competition, all these other kinds of theories that are used to explain the way animals behave and how they interact.

that uses the concept of the selfish gene very centrally to it and you couldn't really understand those kinds of theories without that so I do think that it is more than just another way of looking at it it has actually had explanatory power as well I want to come back to evolution a moment but to stick with this what do you think about the ideas of genetic you obviously don't give much credency any ideas of genetic determinism do you oh I mean I think I do I mean if you're in the laboratory where I work up

People work on diseases like cystic fibrosis or muscular dystrophy and so on. It's utterly foolish to say that there's no such thing as genetic determinism. I mean, genetics is tremendously important. Roughly speaking, two people out of every three, listening to this program, will die for reasons that are directly connected to the genes they carry. The proportion might, as we learn more, might even go up. So there's genetic determinism in that sense. But I often think that genetics tells us everything about,

it's important about being human, apart from the interesting stuff. When we get to things like free will, society, politics, genetics, genetics really can't tell you very much at all. I mean, if you talk about the sexual selection game, I mean, we have and have had in the world

many, many different systems of sexual behaviour. You've got polygamy and so on. You've got... In our own societies, we've sort of changed in the last 50 years to a kind of serial monogamy as an acceptable way of life.

Now, that's happened in a time that's an instant to evolution. It could not have evolved. Our behaviour has changed for purely social reasons. And really, that's the thing which is unique about the human species, where the one creature that doesn't evolve in the traditional Darwinian way, the site of our evolution has moved from body to mind. And that is so important that the bodily constraints are really begun to lose their power. Well, isn't that something you were saying in your book as well, Matt Ridley,

that there are other sorts of determinism? Well, yes, I mean, I certainly think that in us there has been a delegation of responsibility, if you like, from the genes to the brain, much more than in most species. Although I do think that there are, we perhaps underestimate the extent to which our evolutionary heritage still influences the way we behave. But I do think it's important when using this word determinism to realize that there are other sorts of determinism than genetic determinism. If you believe that your character and personality was formed by your upbringing, that's just as determinism. as saying that it was formed by your genes. But is there any way of measuring? How much your personality is formed by your genes?

How much by your parents? How much by your peers? Are we anywhere near a measure? Look, the 33, 33, 33, or 40, 20, 40, or whatever. I think there is. I mean, I do think it's misleading to put an exact figure on it. And because often what you're talking about is the genetic influences that only take place in certain environmental conditions, et cetera.

So the two work together. They don't work in opposition. But the studies of twins in the past 20 or 30 years have now been made very systematic and well controlled. They started out, interestingly, these studies, attempting to establish the power of environment. In other words, they separated twins, brought up in different environments, were expected to show differences that proved the power of parental influence and so on. And frankly, they've produced exactly the opposite results. They've proved that something like half or 40% of personality

with the proviso that that's a meaningless figure comes from inside us, from the genes largely, and a large chunk comes from the peer group environment, but terribly little seems to come from our parents. That result comes up again and again. Now it may at some point be proved to be wrong, but so far it's looking pretty robust. Steve Jones, are we still evolving,

is what's happening to us that's interesting, as you say, to do with the culture that we've created, which has very little to do with evolution in the Darwinian sense? I would say the latter, really. I mean, when we talk about variation in personality and behaviour, I notice I'm talking to two Oxford graduates here. Now, who's to deny that to one's environment is important? What I find extraordinary, and I don't put Matt really into this context,

is those who believe most passionately in the power of the genes are the ones that send their kids to private schools. Now, if the genes are so important, why not send them to your local sink comprehensive? You know, the genes are important in a very, very obvious way. Genes make brains, brains make behavior. But we can do far more to improve the prospects of our children by changing the environment than anything we can do with the genes. So why all this fascination with genes?

I don't understand it. But let's get back to a point that maybe I expressed too bluntly, but I'm going to come back to it. Do you think that we, individuals, human beings, Is there any measure in which we are still evolving? Are our toes getting less useful and shrinking? Are our brains getting bigger? Are we going to change in the next 10,000 years?

Or are we on a completely different route now that we are so much in control of so much of our culture in the widest sense in terms of medicine and habitation and so on? I'm less optimistic than to suggest that the latter is true. I mean, let's take, for example, a nasty piece of it. of evolution that started happening to us in the last 20 years, which is the spread of the AIDS virus. Now, you know, that's really a terrifying event, far more terrifying than most people realize, given the situation in Africa. It's clear now that there are some people who can become infected

by AIDS, the virus, and not develop the disease at all. And the reason, it turns out, is that they carry a particular genetic variant that makes that virus, make it very hard for the virus to get into their cells. They will survive, they will pass on their genes, therefore, in years to come, we may well evolve some kind of resistance to AIDS. Now, so we are evolving in that sense. However, having said that, the thing which is most astonishing about us as a species

is how little we have evolved in the last 100,000 years or so, let's say. If, as I often say, if a cromagnol man from thousands and thousands years ago were to get onto me, onto the next seat to me in the tube, particularly in Camden Town where I live, you know, I really wouldn't

think twice about it. I mean, I might think of another Camden native, why on I move as I think almost every day. But of course his life and experience was unutterably different from anything that we know, completely different, but his body was much the same. And I rather think that's what's likely to happen to us in the future. We will evolve in the sense, for example, that because people move, our skin colour will change, I'm sure, over the next few thousand years to a sort of muddy brown over the world.

But I think our societies will evolve much faster than that. I think there are things that have gone on under the skin, as it were, us that show evolution in action. I mean, for example, the tolerance of lactose, of milk, is something that's changed dramatically. You know, we can drink milk as adults in most of us in this society. A lot of people in different societies in the world can't, and that's an evolutionary change that's happened with the invention of dairy farming, for example. And even today, the invention of in vitro fertilization, particularly some of the later

forms of it, mean that infertility no longer means that you're infertile, if you see what I mean. I realise I'm talking to two men who've written books which are packed with information, full of all sorts of entertainment as well as well as theory. So I'm just nipping in and out. But I don't have finished the programme without going into the business of genetic determinism with regard to... Let's take one example, the plea for the criminal gene. We have the Stephen Mowgli trial, defence, as it were, saying, I come from a criminal family, therefore I'm a criminal,

therefore I'm not responsible, therefore I must be let off or treated, whatever. Now, I get an impression of complication from your book, Matt, and certainly from your book, Steve. Are we anywhere near that possibility of saying that particular gene, number X on chromosome number, is responsible for that particular thing? A, are we near it? And if we are, what does that imply? I think we're near it in a few cases.

I mean, I think there are going to be some very rare cases where violence clearly does run in a particular family, and it clearly runs in that family because there is a particular gene that is different in that family. Has that been proved? They've checked right down the family. Yes, there have been one or two cases of that. But on the whole, what you're going to find is that there are a number of genes to do with sort of the testosterone system that cause young men to go through a period when they're more violent at the start of adulthood. in certain environments and not in others.

And as Steve says, there's very little genetic that one would want to do about changing that. I think the interesting thing about, as it were, a genetic plea, I couldn't do it because my genes made me do it. There's no difference there between that and a plea of temporary insanity, which we're quite used to dealing with in the courts. We draw the line in the grey area.

We say, hang on a minute, there's a certain, you know, there's a degree of insanity that we accept as an excuse, and there's a degree that we don't, that we say, no, you have responsibility for your actions. What fascinates me is the way people actually are very ready to surrender their free will. They rush to the horoscopes to see what's going to happen to them, as if it was determined by them. They believe in all sorts of other ways in which their characters were formed.

People aren't all that ready to accept free will. We have got free will because our determinisms interact. I mean, my determinism interacts with yours, and that ends up being hurriedly unpredictable. Much of you over this day? I think that's clearly true. The interesting thing, though, is let's take this case of this American who used the genetic defense in Georgia.

He's still on death row, waiting for the court's decision. The state of Texas has changed its rule effectively to make it the case that anybody who says that they were under genetic control, they should be executed because they can't be cured. So you can take the same facts and interpret them in two different ways. Your hero, Charles Darwin, described free will as, quote, a delusion caused by our inability to analyze our own motives. You know, I didn't know that.

I should put that in my next book. I think it's in my book, actually. Just on that, I do think it's interesting that we, if environmental determinism, determinism by our upbringing, is external, it comes from outside, genetic determinism comes from within, and in the end it's a contest between what comes from inside us and what comes from outsiders.

And if you put it in those terms, what comes from inside us is not so frightening. We began this program. I quoted Matt Ridley's saying this is the greatest intellectual moment in history. What's your view of that, Steve? This today, this the century. I'm kind of forced to agree, I have to say.

I mean, in biological history, that's for sure. Biologists always have this terrible thing called physics envy. We all wish we were physicists. We're not smart enough to be physicists. So if we exclude Newton from this, and Einstein, I would say, Well, thank you both very much. That's our first row.

They're terrific books, Almost Like a Whale by Steve Jones and Genome, The Autobiography of the Species by Matt Ridley. Thank you very much for listening next week. We'll be talking with Marina Warner and John Alan Palos. That's it. Thanks for listening. Goodbye. We hope you've enjoyed this Radio 4 podcast.

You can find hundreds of other programmes about history, science and philosophy at BBC.com.com.uk forward slash radio 4.