DNA methylation and posttranslational histone modifications. There is also evidence that changes to the epigenome resulting from developmental perturbations are potentiated by exposure to further insult (a “second-hit”) later in life (Hellemans et al., 2010; Park et al., 2017; Seo et al., 2016). A second-hit, in the form of either another stressor, alcohol exposure, or infection, could cause an individual with already altered levels of epigenetic regulators to have more significant adverse outcomes, including those in the realm of learning and memory (Guan et al., 2015; Roth et al., 2010).
