Geneimprint
28 June 2008: Not all multigenerational effects are transmitted through the germ line. Elegant studies in rats demonstrate that generation-to-generation attainment of the nurturing behaviors of pup licking and grooming and arch-back nursing are not germline inherited. Rather, they are passed on to the offspring directly from the mother during the first week of postnatal life through the induction of DNA methylation and histone alterations in the hippocampus (Weaver et al. 2004). Moreover, the inherent plasticity of the epigenome allows for the reversal of these modifications in adulthood by exposure to epigenetic therapeutic agents (Weaver et al. 2006).
But, is there any evidence of epigenetic programming after birth affecting human behavior? Yes, Moshe Szyf and his colleagues have now published in Plos One (McGowan et al. 2008) that the protein synthesis machinery in the suicide brain is aberrantly regulated in the hippocampus of the brain because of a promoter-wide increase in the DNA methylation of rRNA genes. The suicide subjects in this study had a history of early childhood neglect/abuse, whereas, the control victims died accidentally and had no history of abuse or neglect. These findings are consistent with the intriguing possibility that early life events can alter the epigenetic status of genes that control neural functions, thereby contributing to individual differences in suicide risk.
Genomic imprinting is an epigenetic form of gene regulation that results in only the copy inherited from the mother or father to function. (Jirtle and Weidman 2007). Read more...
The hypothesis of fetal origins of adult disease proposes that early developmental exposures involve epigenetic modifications, such as DNA methylation, that influence adult disease susceptibility (Jirtle and Skinner). Read more...
An epigenetic change alters the phenotype without changing the genotype. As a result of their unique genetic make-up, imprinted genes act as nodes of susceptibility for asthma, cancer, diabetes, obesity and many behavioral and developmental disorders - a list that is surprisingly long given the limited number of imprinted genes identified so far. Read more...
