Epigenetics — the science of gene expression is a moving target. Over the past thirty years geneticists recognised that the way a gene is expressed can be influenced by environmental factors. A mother’s obesity, diabetes stress or even mental illness can be passed onto her offspring even if the condition is acquired by her diet or lifestyle. The epigenetic tags, that determine how those genes are turned on or turned off can be inherited. A new study, described in a recent New Scientist, shows that the epigenetic tags for male sperm can be also be passed on. Jerome Jullien at the Wellcome Trust CRUK Gurdon Institute in Cambridge demonstrated using frog embryos that some reprogrammed genes may be passed on.
The result, if confirmed, has far reaching implications. Before this study, researchers assumed that male epigenetic tags would not be passed on to their children. That the epigenetic slate was wiped clean between generations. That way, epigenetic changes would have no role to play in what characteristics are passed on by evolution. But if epigenetic tags are passed on from generation to generation, this would open the door to a Lamarckian version of evolution, where some acquired characteristics can be passed on. This would mean nothing short of questioning natural selection as understood by most evolutionary biologists today.