Social Environment and DNA Methylation: A Mechanism for Linking Nurture and Nature

Abstract

During cellular differentiation cell type-specific DNA methylation patterns are formed which are conserved during life maintaining cell type identity. Cellular differentiation is an innate process. It was therefore believed that DNA methylation patterns remain stable after cellular differentiation and mitosis are completed. Recent data suggests that DNA methylation patterns could also differentiate in response to external social signals in post-mitotic cells after birth and in adults. This raises the attractive possibility that DNA methylation can serve as a mechanism for adapting genomes to changing social environments conferring upon DNA an identity that is "environment-context" specific. DNA methylation is proposed to serve as a genome adaptation mechanism, adapting genome function to changing environmental contexts including social environments. A critical time point for this process is early life when cues from the social and physical environments define lifelong trajectories of physical and mental health. We suggest that we broaden the definition of DNA methylation as a mechanism of conferring differential identities to similar gene sequences. This expands the role that DNA methylation could play beyond the traditional boundaries of cellular differentiation.