On Epigenetics

Identically Different: Why You Can Change Your Genes 

By Tim Spector – the Guardian on 08/08/12

Epigenetics is one of the keys to explaining the mystery of life, writes Peter Forbes

Extract:

“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.”