大象传媒

Adam Rutherford asks how much of our lives' experiences, such as diet and pollution, is passed onto our children, as well as our genes. These changes are called epigenetic.

Throughout our lives our genes become changed by the environment - by things such as our diet, radiation, pollution and smoking. These events have consequences for our health. The view from classical genetics was that we don't pass on any of these defects onto our children. When we reproduce, the genes in our eggs and sperm are wiped clean.

In the 1980s there was the realisation that a child's genes are not always stripped of the experiences of its parents. In other words, what parents do in their lives can be passed onto their offspring. In the last few years, there has been a massive increase in the amount of research into what's called epigenetic inheritance. This year scientists have announced that work in rodents has shown that poor diet and parental neglect can be seen in the genes of their offspring. Another piece of research in rats, published in Nature, demonstrated that if fathers had a high fat diet, their daughters can develop a form of diabetes, even though they themselves weren't overweight or eating a high fat diet. This means that the fathers' sperm had been irrevocably altered by what they had been eating.

And there are some studies in humans that suggest that epigenetic effects are at work. These are retrospective studies, as it is impossible to control the lives of people in same way as researchers can with laboratory rodents.

Researchers have been following the outcome of the women who were pregnant during the prolonged famine in Holland at the end of the Second World War. Girls born to these women have been found to have twice the usual risk of developing schizophrenia. The lack of food produced changes in the mothers' DNA which could have caused changes in the brain of the daughters.

Producer: Deborah Cohen.