Identically Different: Why You Can Change Your Genes by Tim Spector – Review20 Aug 2012 The Guardian
Epigenetics is one of the keys to explaining the mystery of life, writes Peter Forbes The Olympic Isle on opening night was "full of noises, / Sounds, and sweet airs that give delight and hurt not". The lion of the industrial revolution could lie down with the lamb. But beneath the fantasy a sewer ran, diverted but untamed: the spectre of doping. And not just doping, because this is the age of genomics: gene doping. The man who came to warn of this prospect is himself a Spector: Tim Spector, professor of genetic epidemiology at King's College London and the author of this book. The means by which gene doping might be achieved (no one is sure whether it has yet been, or in practice can be, done) is Spector's field of expertise: epigenetics. So he has become a media pundit during the Olympics, but his real subject is twins and what they tell us about genes. Identical twins are a unique test of genes in action because, having come from a single fertilised egg, they have identical genomes, all 3bn letters of them. They are clones. The point about twins and identical genes is that genes in action do some strange things that we are only just beginning to understand – identical genes can diverge in their expression during the course of a lifetime. This is epigenetics. It is now generally accepted that personal experience can change our genes. If you practise music for six hours a day and become a great musician, your brain will show recognisable changes both in large-scale anatomy and genetically. London cabbies have "knowledge" – enhanced regions of the brain that start to recede when they retire. The chemical processes that alter the genes in epigenesis – methylation and deacetylation of the packaging proteins of the genes, the histones – are fairly well understood. But the puzzle is that some of these changes can be passed on to offspring, and the effect – although it eventually disappears after three to four generations – can have profound consequences. One hundred and fifty years of biological orthodoxy claimed that these phenomena were impossible. What is supposed to happen at reproduction – and mostly does – is that all the epigenetic marks acquired during life are erased and every birth is a fresh start. But the case of Dolly the sheep and other animals cloned since then show that where adult cells have been reprogrammed to wipe out the epigenetic marks, the process is inefficient. So Dolly, whose parent cell was six years old, was not really a fresh start. She died prematurely as a result. But even in normal reproduction, it seems that some epigenetic marks can persist for a few generations. Spector explains these facts clearly and does not overdo the deep biology. Most of the book consists of case histories and studies of the crucial traits that matter to all of us: intelligence, athletic and artistic skill, disease, obesity, sexual orientation. What the genomic revolution has done is to reopen the old nature/nurture debate. How wildly this has lurched, protagonists on both sides blithely ignoring what little evidence there was. Spector recalls that in the 1960s and 70s it was almost possible to obtain funding for research on twins because of the prevailing blank slate, nurture-is-all ideology. This was preceded by the appalling eugenics period when, despite the evidence that hereditary genius dissipated over the generations, far too many serious biologists endorsed the idea of breeding the best and brightest and preventing this in the unfit. Today there are fewer excuses because the solid evidence is piling up. But the evidence is often puzzling. To the embarrassment of the Human Genome Project, researchers have come to the conclusion that the genetic component of some multi-factorial diseases is exceptionally low. Many genes have been found to be implicated in such conditions but their overall contribution might be as low as 2%. Like most writers on genetics these days, Spector has to reiterate, yet again, a health warning: genes are not "for" bodily attributes: only about 2% of the genome is literally "for" anything at all: the target is proteins not traits, and what the proteins do next depends on concerted action with other proteins. They nudge and tweak one another (up and down – regulating, according to the jargon). Yes, there are cases in which a single mutation in one of the 3bn bases in DNA causes disease. These are single-gene disorders such as muscular dystrophy, cystic fibrosis, sickle-cell disease and Tay-Sachs syndrome but they are the exception. In these cases, the gene codes for a vital metabolic protein – and to harm it is to throw a huge spanner in the works. For decades, the 98% of the genome that doesn't make protein was dismissed as junk DNA. Some of it is now known to regulate the expression of protein-making genes; much of it is still dark matter. Nevertheless, Spector is able to attach some fairly reliable figures to the heritability of many traits. Where there is autism in an identical twin, there is a 60% chance the other will have it. More surprisingly, Spector reports "a 40%-50% genetic component to belief in God". But you don't live your life by percentages: your life is 100% yours – genes, good and bad luck, roads not taken, all included. Spector has done a good job in revealing how human variability works. On the one hand, there are twins separated at birth who meet decades later wearing the same clothes, with wives bearing the same forename. On the other hand, there are twins who grew up together who diverge in sexual orientation, wealth and health. Genetic determinism is still prevalent in our culture and Identically Different is a necessary corrective. Epigenetics will revolutionise medicine and it is one of the keys to explaining the mystery of life. But, as Saul Bellow wrote: "In our world it appears that as soon as a clear need appears, it is met falsely. It becomes a new occasion for exploitation." The idea of gene doping is to shortcut the epigenetic changes wrought by the 10,000 hours of practice that lie behind every artistic and sporting genius simply by adding or subtracting epigenetic marks to or from certain key genes. Spector said on BBC2's Newsnight that many people in sports genetics believe they have a list of more than 100 possible candidate genes for epigenetic enhancement (although in the book he appears to be sceptical). One must hope that this shortcut to glory will prove as illusory as the dream of cloning pets. Cloned cats are not true to the original in coat colour because that trait is an unpredictable epigenetic phenomenon. - Read More
Dr Michaela Livingstone reviews Professor Spector’s talk at the Cheltenham Festival25 Jun 2012 BioNews
Epigenetics. What on earth is that? You're probably aware that the genetics vs environment debate can still divide people to this day, but epigenetics is something that we haven't quite got around to talking about much in the public sphere. And for good reason. It's not the most straightforward idea to get your head around. So my expectations of the reaction of the audience to Professor Tim Spector's talk at Cheltenham Science Festival this year, not having read his latest book on the subject, 'Identically Different: Why You Can Change Your Genes', was that of stunned silence and confusion. I was wrong. Read in full at http://www.bionews.org.uk/page_153192.asp - Read More
Identically Different: Why You Can Change Your Genes by Tim Spector17 Jun 2012 Sunday Times
Scientists may tell us that our genes are our destiny, but this fine study of identical twins shows this to be anything but the case.
Bryan Appleyard Published: 17 June 2012
Nicky and Louise are 30-year-old identical twins. They are attractive, competent women and, as you would expect, have a lot in common - taste in food, drink and clothes, and a commitment to exercise. They avoid dangerous sports, cigarettes, drugs, and gambling. As identical twins have exactly the same genes, there you have it, proof positive, it’s all in the genes.
Except it isn’t. Nicky has had five men in her life, Louise 25. Even though they like the same kind of men and both enjoy sex and have orgasms, their attitudes are utterly different. Aged 15, they discovered that their father had kept a secret mistress for years. Nicky took it badly; Louise didn’t, and, at that point, their sexual trajectories diverged.
But why? The short answer is that identical twins aren’t identical and our genes are not our destiny. Tim Spector is a professor working in genetic epidemiology at King’s College, London. He made the headlines and outraged many “sex counsellors” when he announced in 2009 that the G-spot (a zone of special erotic sensitivity in women) did not exist.
He also used to think genes were the heart of the matter. “Until three years ago,” he writes, “I was one of the many scientists who took the genecentric view of the universe for granted…But I had a nagging doubt that we were missing something.”
Spector is not alone in experiencing a Damascene conversion from gene-centrism, but with this eminently readable book he is the first successfully to explain the issue to the general reader. In 1993 he started the UK Twins Registry of 11,000 twins, which is now one of the best databases of its kind in the world. Identical twins are one of the gold standards of genetic research; they have the same genomes, therefore any variations or similarities in them provide evidence of the influence of the genes. Spector’s doubts emerged as the variations revealed by his database became ever more apparent.
These variations need not be minor, they may be a matter of life and death. Twins Peter and Nigel, for instance, were ready to celebrate their 42nd birthday together when Peter hanged himself. Depression ran in the family but, although identical, only one of the pair seemed to have inherited the trait. Even conjoined twins such as Ladan and Laleh in Iran exhibited striking differences. Laleh liked computer games, Ladan liked praying; Ladan was left-handed, Laleh right-handed. They died in the operation to separate them in 2003. Doubtless, if they had lived apart, they would have diverged even further. The point here is that identical twins do not prove the power of the gene, they define its limitations.
Now, full disclosure — I have a dog in this fight. In the 1990s, while writing a book on genetics, I became baffled by the arguments of the gene-centrists. Following Richard Dawkins, who insisted we were lumbering robots operated by our genes, the gene-centrists claimed that our genomes did almost everything and that whatever remained could be explained by the “environment”, an entity that remained undefined. This position was riddled with unfounded assumptions and contradictions but, whenever I pointed this out, the scientists merely looked at me pityingly. Anyway, just to say, thanks, Spector, for backing me up.
The defeat of the gene-centrists began with the over-hyped publication of the human genome in 2000. This was, it was claimed, “the book of life” — it isn’t — and was to be the prelude to a revolution in medicine — so far, no. The first sign there was something wrong was the revelation that we have only about 23,000 genes, half as many as a tomato, and only a quarter as many as, in our vanity, we thought we had. The second sign was that the gene-centrists’ belief in the simple link between genotype and phenotype (organism) was naive; vast complexity was the harsh (but, for me, consoling) reality.
One genetic fundamentalist claim after another collapsed — there is no gene for homosexuality, none for alcoholism and so on. It is probably true to say that the phrase “gene for” is usually meaningless. This is partly because many genes are involved in almost any trait, but, more important, it is because (as Spector surmised) there was something missing.
What was missing is now called epigenetics, a concept whose importance can scarcely be overstated. The gene-centric view was that the gene produced a protein that went on to build an organism. In fact, we now know not only that some genes can produce several proteins, but also that this mechanism can be turned on and off by processes of which, not long ago, we knew nothing. The gene, in other words, is not the last word and may not even be the first. It is certainly not in complete control of anything.
The implications are staggering. The first is that twins may not be identical because these processes (the most common is called methylation) could have happened to them in the womb. Second, the sins of the grandparents can be visited upon the grandchildren. Spector has cases of one generation’s starving and binge-eating during postwar austerity resulting in
obesity two generations later. In other words, what you do in life may affect the genomes of your offspring.
This book concludes with a list of four genetic dogmas that have been overthrown: genes are not our essence; our genetic inheritance can be changed; environmental events can be “remembered” by cells; and what happens in your life can affect later generations. Or, to put it bluntly, almost everything you’ve been told about genetics is wrong.
The list also, potentially, settles the old, stale and often irrational argument about nature v nurture. What epigenetics demonstrates is not a simple division between humans and their environment (the underpinning of much of the illogic spouted by the scientists I met in the 1990s), but rather a flow of indecipherably complex interactions, a ballet of cells that, in some ways, matches the flowing, dancing world of particles and forces discovered by the physicists beneath the surface of matter.
This is not simply a book of ideas, it is also a book of stories, most astounding, many heartbreaking. Flo and Kay, for example, were an incredibly rare case of “idiot savant”, identical twins who found peace in the American television quiz show Pyramid. When it ended, they found further consolation in the idea of being buried with memorabilia of the show’s host Dick Clark. There are twin sisters, one of whom has frequent orgasms and one who didn’t have one until she was 42. There is a twin who conspires, unsuccessfully, to have her identical twin murdered. Most alarmingly, there is the story of a substance in almost all plastic that may epigenetically alter our genomes. If proved, that, I imagine, will make the euro meltdown look like a very small disaster indeed.
Spector will get you through many dinner parties. But, much more importantly, he will show how a certain kind of scientific fundamentalism collapsed under the burden of its inability to explain the world as it is – complex, flowing, changing – rather than as they would like it to be – simple and clear. Read him.- Read More
Centenarians vs newborns: Epigenetic differences reveal clues to ageing15 Jun 2012 BBC
It's pretty easy to spot the difference between a newborn and a centenarian, but explaining how and why we age is far more challenging. Why do we develop wrinkles and why do our muscles waste away? Why do our brains and immune systems become less effective with time? In the search for clues to what is going on, researchers in Barcelona have looked in huge detail at the "epigenomes" of a newborn baby boy and 103-year old man. It's all part of the rapidly emerging and exciting field of epigenetics. View the whole article on the BBC website HERE - Read More
Identical twins show the malleability of our genes13 Jun 2012 New Scientist
"AN APPLE, cleft in two, is not more twin than these two creatures." This line, from Shakespeare's Twelfth Night, plays on the similarities between (supposedly) identical twins for comic effect. But for all their uncanny similarities, identical twins are not simply two uniform halves of a single whole. As Tim Spector explains in this fascinating and provocative book, despite sharing the same sets of genes, such twins differ in many important ways. These differences are giving new insights into how our genes and environments interact - and raise the question of whether we have more control over our genetic destinies than we might think. View article on the New Scientist website HERE. - Read More
Book reviews for The Diet Myth
The Diet Myth is fascinating, and I'm now obsessed with microbes!
A fascinating and original look at the impact of food on our bodies underpinned by cutting-edge research.
It's not often that a book changes my life in a mere three chapters ... given my usual reluctance to jump on any nutritional bandwagon, I reckon this makes Tim Spector's work a rather compelling read. ... It's truly eye-opening stuff, and we owe it to ourselves and the 100 trillion friends inside our bodies to read this book.
Felicity Cloake, LITERARY REVIEW
I don't read diet books and I certainly never plug them, but The Diet Myth is a worthy exception that provides new insight into why we should think twice about what we put in our mouths.
Dr Mark Porter, THE TIMES
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