For the first time, we have a mechanism that could explain how your lifestyle choices may impact the genes of your children and grandchildren.
Mounting evidence suggests that environmental factors such as smoking, diet and stress can leave their mark on the genes of future generations.
For example, girls born to Dutch women who were pregnant during a long famine at the end of the Second World War had twice the usual risk if developing schizophrenia.
This is puzzling – although we know that the environment can alter how our genes are expressed through structural changes to our DNA, classical genetics says such epigenetic markers are stripped from our genomes when we are early embryos.
But now researchers have observed some human genes evading this clean-up process.
Azim Surani at the University of Cambridge and colleagues found that a bout 2-5% of DNA methylation (a form of epigenetic tag that makes genes less active) escapes the reset process that happens during early embryonic development (Tang et al., 2015).
Because this is only a small proportion of the genome, Surani says most epigenetic changes caused by our environment are very unlikely to affect future generations, but that there may be a small window of opportunity for some to be passed on.
They found that these “escapees” were mostly genes implicated in brain conditions such as bipolar disorder and schizophrenia, as well as metabolic disorders like obesity.
New Scientist (2015) First Evidence of How Your Lifestyle Could Shape Future Genes. New Scientist. 13 June 2015, pp.17.