Epigenetics and the Biological Basis of Gene x Environment Interactions

Sackler Program for Epigenetics and Psychobiology, McGill University and Douglas Mental Health University Institute, Montreal, Canada.
Journal of the American Academy of Child and Adolescent Psychiatry (Impact Factor: 6.35). 08/2010; 49(8):752-71. DOI: 10.1016/j.jaac.2010.06.001
Source: PubMed

ABSTRACT Child and adolescent psychiatry is rife with examples of the sustained effects of early experience on brain function. The study of behavioral genetics provides evidence for a relation between genomic variation and personality and with the risk for psychopathology. A pressing challenge is that of conceptually integrating findings from genetics into the study of personality without regressing to arguments concerning the relative importance of genomic variation versus nongenomic or environmental influences.
Epigenetics refers to functionally relevant modifications to the genome that do not involve a change in nucleotide sequence. This review examines epigenetics as a candidate biological mechanism for gene x environment interactions, with a focus on environmental influences that occur during early life and that yield sustained effects on neural development and function.
The studies reviewed suggest that epigenetic remodeling occurs in response to the environmental activation of cellular signalling pathways associated with synaptic plasticity, epigenetic marks are actively remodeled during early development in response to environmental events that regulate neural development and function, and epigenetic marks are subject to remodeling by environmental influences even at later stages in development.
Epigenetic remodeling might serve as an ideal mechanism for phenotypic plasticity--the process whereby the environment interacts with the genome to produce individual differences in the expression of specific traits.

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    • "In particular, the Novosibirsk group has long argued that hormonal states in the mother, associated with the less stressful conditions of domesticity, are involved in generating the DS (Belyaev 1979; Trut et al. 2004, 2009). Findings consistent with this idea, though opposite in effect, involve maternal stresses in mice that create epigenetic chromatin state changes and behavioral phenotypes in offspring (Meany and Szyf 2005; Bagot and Meaney 2010). Whether epimutations have the requisite stability in transgenerational transmission to generate true heritable states is always a key question about their evolutionary potential (Slatkin 2009) but strong trans-generational transmissibility of epigenetic states has been shown for two genes affecting coat color patterns in the mouse, Agouti and Axin Fu genes (Morgan et al. 1999; Rakyan et al. 2003). "
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    Genetics 07/2014; 197(3):795-808. DOI:10.1534/genetics.114.165423 · 4.87 Impact Factor
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    • "On the negative side, there is evidence from multiple lines of research that hippocampal development is profoundly disrupted by negative environmental influences like maternal stress, chronic stress during childhood, and maltreatment (see Farah et al., 2008; Meaney, 2010; Tottenham and Sheridan, 2009). Thanks to extensive research in non-human animals, much is known about the underlying molecular and cellular mechanisms (e.g., Bagot and Meaney, 2010). There is also a growing body of literature indicating that PFC development is affected by chronic stress, intrauterine drug exposure, lead exposure during childhood, and other environmental factors (see Mackey et al., in press). "
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    • "Parental effects occur when the phenotype or experienced environment of one or both parents influences the phenotype of their offspring apart from the effects of direct genetic transmission (Marshall and Uller 2007). Parental effects can be a result of one or both parents influencing offspring phenotypes via nest site selection, nutrient provisioning, hormone transfer, providing particular social experiences or serving as a mentor or model from which to socially learn, and epigenetic modification of gene expression may be an important proximate mechanism (Bagot and Meaney 2010; Crews 2010; Curley et al. 2011). Behavior can act as both a generator and a target of parental effects as parental behaviors may affect nonbehavioral traits in the offspring (for example, parental provisioning behavior may affect offspring size) and nonbehavioral traits in the parents may affect offspring behavior (for example , the deposition of androgens in eggs may increase the aggressiveness of the offspring) (for recent reviews, see Marshall and Uller 2007; Badyaev and Uller 2009; Maestripieri and Mateo 2009; Wolf and Wade 2009). "
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