Epigeneticist Tim Spector has discovered that genes affect everything from sexual preference to drive and motivation and the ability to be happy. And we can change how they work

Tim Spector spent the first part of his career trying to persuade people that your genes were your genes, they determined your biological fate and there was nothing you could do to change them. Even the title of his first book, Your Genes Unzipped: How Genetic Inheritance Shapes Your Life, goes someway to showing what his opinion was as recently as 2003. “People loved the research but not the message,” says the professor. “It was disheartening obviously for people to think that there was nothing they could do.”

Now, after new research using identical twins at King’s College London, Spector is saying the opposite: genes previously thought to be fixed entities can change over the course of your life, changing your susceptibility to disease and other biological issues (weight gain, blindness, sex drive, depression). What is more, your behaviour can change them. “It took me a while to come round to the fact that what I had been trying to convince people of wasn’t what the research was showing,” says Spector, who grew up in Heath Street and is a former UCS pupil. “That is the exciting thing about science, things can change. It really energised me to do more research.”

His new book, Identically Different: Why You Can Change Your Genes, is the culmination of research on the genetic behaviour of twins. The idea is that twins are born genetically identical, yet over the course of their life their bodies and minds can diverge, leading them to be very different. “Although they are genetic clones,” explains Spector, “and usually live similar lives – strangely they don’t usually die from or develop the same diseases.” An example of this is one twin developing breast cancer, while the other one usually doesn’t – something that Spector is now researching. This whole phenomenon of genes changing by being switched on or off in this way is called ‘epigenetics’.

The book takes us chapter by chapter through different types of research into how genes affect everything from sexual preference to drive and motivation and the ability to be happy. Spector explains that our behaviour can reprogramme our genes through various research he has collected. The research is written in an entertaining and lighthearted way – Spector has written the book for non-specialists and makes quite complex science easy to understand and fascinating.

“We are so obsessed with long-term evolution and Darwinism that we haven’t paid much attention to short-term evolution” says Spector. “It is a part of our ability to adapt as humans.”

The findings mean that, as a result of direct action, your genes and their capabilities may change, seeing off the old accepted wisdom that you will inevitably inherit your parent’s depression, alcoholism, poor eyesight or tendency for weight gain and there is nothing you can do. “An example is people who exercise three times a week can modify the way their genes that control appetite work – making them less susceptible to obesity problems,” says Spector.

Remarkably, Spector has also found that you can pass on these good modified genes to your offspring, breaking the chain of ‘bad DNA’. This puts paid to the idea of someone being from ‘good stock’ – as lifestyle affects who you are and what you become as much as what your parents have passed down.

These findings have significant ramifications – the idea that genes can change through behaviour means that theoretically we can purposely target our genes for enhancement of our physical capabilities. Spector was approached during the Olympics to comment on whether ‘gene doping’ for sports, meaning specifically targeting genes with chemicals for performance enhancement, was possible. “It is, in theory, possible and no doubt someone, somewhere is working on it. We are already epigenetically targeting our genes on a crude level with things like folic acid, for example.”

Given the findings about how exercise can affect your genetic make-up, surely even training is a way of isolating genes and targeting them? “Yes, in a way you could say that exercise is a form of gene doping. The ethical difference is that everyone has access to exercise, but not everyone has access to a geneticist who can target your genes scientifically.”

Genetic targeting may be what the future holds for us, not just in sport but in many areas of life. Currently Spector is using the research to look into breast cancer, depression and diabetes. “Comparing the DNA of one twin with breast cancer, with the other who doesn’t, you can trace the beginnings of the cancer epigenetically five years before clinical diagnosis. This means that in susceptible people we may be able to screen DNA and change its make-up before the cancer has time to fully develop,” says Spector.

Is he enthused about these new, potentially life-changing findings? “Yes they are very exciting,” he laughs. “They just take much longer to find than to publish.”

Identically Different: Why you can change your genes by Tim Spector is published by Weidenfield and Nicholson �20.00