We just can’t help it. This epigenetics stuff really floats our boat. The last few weeks we’ve brought you a Dear Mark primer on gene expression as well as news on recent studies examining the role of lifestyle/environment on genetic expression. Diabetes, heart disease, even lung function are impacted by external factors like nutrition, exercise, and pollution exposure. But mental health is part of the epigenetic picture as well: chronic stress and even early emotional experiences, it turns out, may be significant enough to alter our genes’ expression.