Dynamic epigenome as interface between environment and genome

The epigenome serves as an interface between the dynamic environment and the inherited static genome. It is comprised of chromatin and a covalent modification of DNA by methylation. The epigenome is sculpted during development to shape the diversity of gene expression programs in the organism's different cell types by a highly organized process. Epigenetic aberrations have consequences similar to those of genetic polymorphisms, resulting in variations in gene function. Recent data suggest that the epigenome is dynamic and is therefore responsive to environmental signals, not only during the critical periods in development but also later in life. It is postulated here that not only chemicals but also exposure to social behavior, such as maternal care, may affect the epigenome. It is proposed that exposure to different environmental agents could lead to interindividual phenotypic diversity as well as to varying susceptibility to disease and behavioral pathologies. Interindividual differences in the epigeA-netic state could also affect susceptibility to xenobiotics.