Department of Pharmacology McGill University Canada
The programming of the genome is accomplished by the epigenome. Two elements of epigenomic control are chromatin modification and DNA methylation. Epigenetic patterns are generated during cellular differentiation by a highly programmed and organized process. Nevertheless, they are dynamic and responsive to the environment especially during the critical periods of gestation and early life as well as later in life. This sensitivity of the epigenetic machinery to the environment offers a conduit through which the environment can sculpt the genome and have a long-term impact on behavior. We will discuss three studies from rat, rhesus monkeys and human delineating the signature of maternal care and social adversity on the epigenome. We used high-density oligonucleotide microarrays combined with methylated DNA immunoprecipitation to map the response of the “methylome” “acetylome” and “transcriptome” in different brain regions as well as T cells and whole blood in adults exposed to social adversity early in life and controls. Our preliminary results indicate a wide signature of early life maternal care and social positioning on the methylome. Our data also suggest evolutionary conservation of the response and its co-clustering in defined genomic regions.