Maternal care, the epigenome and phenotypic differences in behavior.
The genome is programmed by the epigenome, which is comprised of chromatin and a covalent modification of DNA by methylation. Epigenetic patterns are sculpted during development to shape the diversity of gene expression programs in the different cell types of the organism. The epigenome of the developing fetus is especially sensitive to maternal nutrition, and exposure to environmental toxins as well as psychological stress. It is postulated here that not only chemicals but also exposure of the young pup to social behavior, such as maternal care, could affect the epigenome. Since epigenetic programming defines the state of expression of genes, epigenetic differences could have the same consequences as genetic polymorphisms. We will propose here a mechanism linking maternal behavior and epigenetic programming and we will discuss the prospect that similar epigenetic variations generated during early life play a role in generating inter-individual differences in human behavior. We speculate that exposures to different environmental toxins, which affect the epigenetic machinery might alter long-established epigenetic programs in the brain.
Szyf
Moshe
M
Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Montréal, Québec H3G 1Y6, Canada. moshe.szyf@mcgill.ca
Weaver
Ian
I
Meaney
Michael
M
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002843:Chromatin / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D019175:DNA Methylation; D004785:Environmental Pollutants / Q000633:toxicity; D044127:Epigenesis, Genetic / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D014644:Genetic Variation / Q000187:drug effects; D018392:Genomic Imprinting; D005838:Genotype; D048788:Growth and Development / Q000235:genetics; D006657:Histones / Q000378:metabolism; D006801:Humans; D008425:Maternal Behavior; D010641:Phenotype; D013312:Stress, Physiological / Q000235:genetics / Q000378:metabolism
D002843:Chromatin; D004785:Environmental Pollutants; D006657:Histones