As hinted at above, new subfields have emerged to explore epigenetic effects in a variety of settings. Described by Reamon-Buettner and colleagues, the field of “environmental epigenetics” studies how environmental exposures affect epigenetic mechanisms (Reamon-Buettner, Mutschler, & Borlak, 2008). Many researchers are interested in uncovering how environmental exposures at sensitive periods of development, such as maternal cigarette smoking during pregnancy, might influence epigenetics and thus affect the developing fetus and fetal programming. Research in both human cohorts and model systems, such as mice, continues to characterize the influence of environmental exposures on epigenetics. Figure 1 describes how certain prenatal exposures may, both directly and indirectly, influence maternal forecasting through epigenetic mechanisms. Additionally, these epigenetic mechanisms, such as DNA methylation profiles or miRNA expression, may have utility not only as diagnostic biomarkers capable of predicting increased risk for behavioral deficits, diseases, or disease progression but also as therapeutic targets. This is similar to recent reports using gene expression differences, identified via a blood test, to predict youth at risk for early onset depression (Pajer, 2012).
