Meeting Abstract

51.6  Saturday, Jan. 5  Epigenetics as a stress response and its differing roles in the embryo and in the adult EPEL, D.; Stanford University depel@stanford.edu

I explore the view that that the adult and the embryo handle environmental change in radically different ways. The adult handles change through reversible and temporary changes referred to as the adaptive stress response. The response can ensue from environmental changes in temperature, xenobiotic, oxygen, nutrients and osmolality etc., The embryo might utilize similar reversible stress responses during the development period, but the most important response to environmental change are embryo-unique adaptive epigenetic mechanisms. The outcome is an irreversible change in phenotype resulting from the deployment of alternative developmental pathways in response to specific environmental signals. The signals that the embryo responds to could come from sensing nutrients, predators, photoperiod, maternal behavior, chemicals and probably a plethora of unappreciated environmental signals. Irreversible epigenetic changes also occur in the adult but these appear to be maladaptive. I end with a discussion of how this reframing of adult vs embryo stress responses provides a new view of epigenetics and its changing role during the life history of the organism.