The Huxley Debate: the truth about epigenetics
By Katie Griffiths, Young People’s Programme Assistant at the British Science Association
Sparks flew at British Science Festival last night as Tim Spector, Professor of Genetic Epidemiology at Kings College, London and George Davey-Smith, Professor of Clinical Epidemiology at the University of Bristol, participated in the inaugural Huxley Debate on the science of epigenetics.
Tim explained that from his point of view, epigenetics is the field that will explain many of the mysteries of genetics that have bemused scientists up until now. For example, did you know that most genetically identical twins actually die from different causes? In fact, if one identical twin suffers from heart disease, the chances of their twin suffering the same issue are still less than 50/50. This clearly suggests that, despite what people have believed for many years “genes are not our destiny”, and, as Tim said, “something else has to be there”. He believes that this something else is epigenetics.
One of the most exciting possibilities of this field, according to Tim, is the possibility that epigenetic changes may be transgenerational. This means that your life could be affected by things that your Grandfather did, and that lifestyle choices you make, such as smoking, might have an effect on your children and on their children too.
George Davey-Smith disagrees with this. He argues that there is no evidence to suggest that epigenetic changes are transgenerational in humans or in any mammals. And, in fact, he says that there’s a huge body of evidence, amassed over the past 100 years, that epigenetic changes have no significant effects on phenotypes in the next generation.
Although epigenetics is a fascinating subject, says George, it shouldn’t change the way we think about genetics or inheritance. The Darwinian and Mendelian models that we have used for all these years are still valid, and epigenetics fits into these models as a mediator of genetic and environmental changes. As for the unexplainable mysteries of genetics? George believes that many of these can be put down to chance events that we cannot predict or study. Perhaps these random changes are mediated by epigenetics, but there is no evidence that they are driven by transgenerational characteristics.
For Tim Spector, this answer isn’t good enough. The field of epigenetics is in its early stages, with exciting developments still to come. Current technology only allows us a glimpse into the complexity of epigenetic mechanisms, and there’s much more to discover about how these processes work. For Tim, the more we study epigenetics, the more we will discover that it does play a role in transgenerational traits. The big question for the future for him is just how big an impact might it have?