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Prof Tim Spector



Tim Spector is a Professor of Genetic Epidemiology at Kings College London as well as the Director of the Department of Twins Research and Epidemiology at St Thomas’ Hospital.  In 1993 he was the founder of the UK Twins Registry which remains one of the largest collections of genotype and phenotype information on twins in the world.  He is also a successful popular science author on genetics.

Perhaps the most controversial is this whole idea of trans-generational change.

On getting interested in science

So, my background’s quite varied, I decided to do medicine quite late, probably because I couldn’t think of anything better to do at the time, and my father was a doctor and he said even if you give up…he was Graham Chapman’s tutor from Monty Python and he’d chatted to him and he finished medical school but never practiced but always said it was a good thing in reserve, even if you do something wacky you’ve got something to pay your salary.  So I was lazy, I probably wouldn’t get into medicine now.  The other thing when I look around at these grades you have to achieve at the age of 15…my grades at 15 were so disastrous I don’t think I would’ve got in to do woodwork at most universities now.

So I did medicine and as I was doing it I found that I liked doing things that I was in charge of, I didn’t like being told what to do – a side of my character.  So I got drawn into research, I felt I could pose my own questions and actually I didn’t mind spending a lot of time doing that if it was on my own.  So I got into a bit of research when I was a medical student did some…something called epidemiology which is looking into risk factors for disease, and I did some little study about coffee drinking and cancer of the pancreas and showed that drinking coffee and eating soya increased your risk of cancer of the pancreas, as did watching TV,  according to the same analysis.

But that got me interested in it, so I finished my training and I then decided, well I still quite like being a proper doctor, and so I did rheumatology, the study of arthritis, but I was always doing a lot of research and I did as little as I could on the clinical side of things in order to do research, went back to do a masters in epidemiology, then got more research grants to study that and I was the world expert in hormones and arthritis for a short time.  Then I had to branch out on my own…set up my own research group, and it was about that time that I said, perhaps I should do something different, and that’s when I started looking at genetics. I had a few months to decide what I was going to do, toured around the country, Oxford, Cambridge, and ended up having a few beers with people and one chap sat down with a beer with me and said, you know, I think twin studies is a good idea, why don’t you do them? And I always like to take credit for me finding that breakthrough, but often it is just chats with other people, some of them you disregard, others ring a bell and this rang a bell and I decided no one else was doing it, what a great idea, and it just seemed exotic at the time.

I set up on my own, I was still quite young, most people didn’t trust me with that money and things, but it was fun.  And then this twin study just got going.  Everyone else had been kicked out of the UK because of the IQ being genetic debate, I was the only one to benefit from that really.  So they went to the US because we had a very socialist government, they didn’t like people doing research into personality and IQ and genetics.  So I did this and I said, I’ll just do arthritis, I won’t do anything controversial,  although I later did and the study went amazingly well, twins were recruited from all over the country, I did a few TV interviews and before I knew it we had 10,000 volunteers.  And the money came with it and everyone wanted to participate and we were able to study everything from arthritis to personality traits, sense of humour, sexuality, political views, belief in God, everything you could play with.  For someone like me who was interested in everything and liked to do new things, it was the perfect ground to look at the nature-nurture debate initially, which was at that time very controversial.

And then gradually I did more basic genetics, had to teach myself genetics because it’s another language – it’s basically like learning languages – and stated doing molecular work, worked with lots of bright people who did all the hard stuff, I just came up with the ideas and got the money.  And then I was doing mainstream genetics up until four years ago when really the point came when I was just preparing for a talk on twins and I got a bit sick of doing the same thing, everything’s genetic, everything’s genetic,  and I started preparing some slides saying, well, isn’t it about what the actual rates of agreement are in identical twins, and saw that actually, for most of the diseases I was interested in, diabetes, arthritis, heart disease, cancer, the agreement was usually only around less than 30 or 40 percent.  So 70% of these identical twins got completely different diseases.  I said, how does that match the fact that all these…we call these highly heritable diseases, very common.  And the other idea was, people die at completely different times, so longevity was perhaps the lowest heritable trait.  And this all started being rather confusing to me. 

I said, how do I match all these things up?  And it was this idea, that I couldn’t match up the fact that identical twins ended up with different diseases and personalities more often than not contradicted with the anecdotes in the press and the media…because isn’t it amazing that every time there’s a documentary on telly it’s, isn’t it amazing that these twins are so similar, they’ve never met each other and they’re wearing exactly the same T shirt.   And you realise that that was just an anecdote and most twins are not like that and we’ve been exaggerating the similarities because people like to…we love to see those similarities and we tend not…if people smile the same way at  you, they look the same way at you, as humans we’re very focused on that and we tend not to go under the surface and pick out the differences. 

And that was the moment I said, right, I’ve got to study this, and the only way to study it was epigenetics.  And I knew very little about it, so I said, I’m going to go away and learn about it and to do that I actually wrote a book – a popular science book is the best way to get a broad knowledge without getting bogged down in all the technical detail and boring stuff –  and so I managed to get a publisher and buried myself away in Spain for a few months and wrote, which gave me the time to actually read all this stuff that I needed to do to sort of convert, cause at that time there wasn’t that much literature, and that’s been the main thrust of my work ever since and I have lots of collaborations and am now starting to get a lot of exciting results from it.

On twin research

I’ve been doing twin research now for over 20 years and basically you can use twins – these are adult twins – in a whole variety of ways to answer all kinds of interesting scientific questions.  So the classical one that most people know is using twins to look at the difference between nature and nurture.  And to do that you take a group of identical twins and compare them with a group of non-identical twins. And if you find there’s greater similarity between the identical twins compared to the non-identical twins for whatever trait you’re looking at, whether its blood pressure or laughing at a Larson cartoon, you can say that that trait is genetic as opposed to just due to the environment.

On nature vs nurture

I think ten years ago there was a real turning point because there was this massive amount of new genetic information. Technology was incredible, we could pick apart the pieces of DNA sequence in everybody relatively cheaply and the hope was that we could predict everything.  So ten  years ago the idea that we have this genome, everybody gets a little test, we can predict everything that’s going to happen to them because we had this incredible technology and we were able to look at all the little tiny bits of all the genes and work out exactly what was going on.

And so people had this idea, a bit like in the film Gattaca, that someone would have a blood test done at birth and you would be able to decide were they going to be going to Mars on a space mission or were they going to be cleaning the streets.  And it was this technology that impressed people rather than what followed later, realising that, actually, our genes are not our destiny, they’re not the main players in what we do.  They’re important, and they always will be important, 50-60% of everything that goes on is down to our genes, but in terms of predicting how we behave, what diseases we get, when we die, when we live, the subtleties of being human, they’re always going to be pretty useless because for most of us, these common events are not driven by single genes, they’re driven by hundreds or thousands and we’ve known about this actually for…since the 1920s when the first twin studies were done, that showed that identical twins, although they’re most similar compared to non-identical twins, are rarely the same, they’re rarely exactly the same and having an identical twin, which is like a clone, is the best you could ever get on any genetic test.  Someone sitting next to you, brought up by the same mother, womb, placenta, school, everything, they’ve got exactly the same genes, the same DNA in every cell in their body, and yet, what happens?  You and your clone, you don’t die of the same diseases, you don’t even get the same diseases, you end up with quite different personalities, you often end up in very different jobs or walks of life, you marry different people, one can be happy, one depressed, you get diabetes, the other not, and all these factors, we tell everybody that …even the best possible genetic test isn’t going to do the business and it’s just one bit of the puzzle. And that’s what we’ve changed in recent years from our optimism ten years ago to realising, well,  hang on a minute, there’s more to this and seeing that, actually, it’s not seeing what genes you’ve got, but how you use them.  What are those extra devices, those extra switches that can turn things on and off, in a more reversible, more flexible way, that makes us uniquely human?

On changes in the field’s mindset

Major changes in our mindset? I think up to about three years ago people thought that epigenetics was just something that happened on a few genes. So there are these so-called imprinted genes that have always had this idea that only one half of the gene gets expressed because of epigenetics.  But by suddenly studying everything, we realised that it was crucial for the whole body and realised that it wasn’t just a random process, it was highly programmed, but also that it was even genetically programmed as well. So the whole thing got vastly more complicated so, from being this small rather niche area, it suddenly became something that…jokingly explained as something that describes the whole rest of the universe, if you don’t know the answer, you say its epigenetics! And that’s a common thing we do in science, you know, it’s the next best thing that could explain everything or nothing.  But I think that change, that it was every single gene is affected by epigenetics which makes it work differently in every cell in our bodies, that was a very major change.

The other big thing, and perhaps the most controversial, is this whole idea of trans-generational change, so if my genes are effaced, epigenetically switched on or off, say by diet or exercise or something like that, can that effect be passed to my son and my grandson? And, if that’s true, what are the implications?  And this is one of the hottest topics in epigenetics at the moment because it changes the way we think about ourselves and our environment, the fact that our environments are changing, does that mean that our genes are changing directly because of our environment, whilst having to wait hundreds of generations.  And the studies, you ask different people, you get completely different answers about what they believe.  The animal studies are getting increasingly convincing that you can do this in experimental animals, both in the males and the females.  Evidence in humans is very weak and so it starts to beg the question, well, if it happens in every animal we’ve looked at but we can’t prove it in humans, are we so special that we say, it can’t happen?

Most people I’m speaking to now are saying yes, it probably can happen in humans, but the next question is it probably doesn’t matter that much, or else we probably would’ve noticed.  You know, we’d have noticed that cause my father ate egg sandwiches, he’s changed my genes, and I haven’t done this. But if you don’t think about it, it’s very hard to think that the life you’re leading might be reflected in the life that your grandparents led, for example, or the fact that they all smoked, some little remnant of that smoking in their DNA has passed down to you and you’re therefore slightly more prone to lung cancer even if you’ve never smoked.  And so, I think, even the likelihood of that being true has a big impact on how we look at society, culture, the things we do when we’re young, wild excesses we do, we think it’s not going to hurt anyone else but us, so a bit like the way pregnant women feel about doing everything they do, are we going to  start changing our views of how we should be eating properly and living these saintly lives if you like, although no one knows what the optimum lifestyle is epigenetically.

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