Smoking while pregnant is bad, leading to increased risk of lung disease, cancer, and obesity in offspring. But how does smoking affect the epigenetic landscape? Bauer et al. investigated this, at a base-pair level, in mothers and their children at birth through 4 years old. They find that maternal smoking targets functionally relevant enhancer elements in the genome, leading to impaired lung function in children. These epigenetic marks are similar across cell types, show stability over time, and occur when epigenetic shifts are most pronounced. Thus, by systematically studying the association between genetic variation and DNA methylation, they document a link between epigenetic changes and environmental exposure.
Mol. Syst. Biol. 12, 861 (2016).