Epigenetics. In International Encyclopedia of the Social & Behavioral Sciences. 2nd ed. (Book Chapter)

The external environment plays a primordial role in determining gene expression, and protein production, which may in turn define a behavioral or physiological phenotype. This control occurs at both the transcriptional and translational levels and involves a wide range of mechanisms, providing a plethora of opportunities for altering the final level of functional proteins. These mechanisms all share the common feature that they do not alter the underlying genomic sequence, but they act as biological annotations to the genome. In this article we review these mechanisms, and how they are related to health. In particular the role of the three epigenetic mechanisms in controlling the glucocorticoid receptor, as well as the stress phenotype, is reviewed in detail.