Article summary of DNA Methylation, Behavior and Early Life Adversity by Szyf - Chapter

Preface

DNA methylation is an epigenetic process in which a methyl group is added to a histone within the DNA molecule. This changes the structure of the DNA, creating tissue-specific DNA methylation patterns. DNA methylation plays a crucial role in determining tissue-specific patterns of gene expression.

DNA methylation in the face of dynamic environments

The fact that DNA methylation plays an important role in the specification of specific cell type programs, implies that DNA methylation is preserved during the lifetime of the tissue. Because of this, it is assumed that DNA methylation patterns are highly resistant to physical tissue. Data have shown that DNA methylation could be involved in providing specific DNA exposure and that these DNA methylation differences are associated with stable phenotypes. This idea is of particular importance for mental health care and behavioral biology. Here, gene-environment interactions have been recorded and the impact of the external social environment on the behavior and development of the brain has been extensively determined.

Working hypothesis: DNA methylation is a potential genomic mechanism for adapting sustainable genome analysis programs of the social environment.

An important part of human and animal development are external environmental signals (stimuli from the environment). In particular, the development of: mental functions, behavior, immunity, inflammation and healthy metabolism. As a result, it is stated that DNA methylation has its share in the form of genome function in response to signals from the environment. Especially the early years of life are important. Social and physical environmental signals in these early years will have an impact on the rest of one's life. So, growing up in an unfavorable environment leads to worse immunity, mental responses and heart responses. These responses in turn change DNA methylation in various physiological systems such as the brain and the peripheral systems.

The effect of maternal care

Maternal care plays a crucial role for the future well-being of her offspring. In this study, it was studied whether natural variations in maternal care just after birth lead to differences in DNA methylation that may lead to observed phenotypic differences between the offspring in adult life. These adult offspring experienced either High Licking (HL) and High Grooming (HG) maternal care or Low licking (LL) and Low Grooming (LG) maternal care. The offspring that received LL maternal care showed an increased level of glucocorticoid in their stress response. It has been shown that variations in maternal care lead to differences in epigenetic programming. These differences remain visible in adulthood. It was also examined whether the change in DNA methylation was reversible, but this was not the case. Early stress in mice causes persistent DNA hypomethylation in an important regulatory region of the arginine vasopressin gene, which plays a role in aggression, blood pressure regulation and body temperature.

Summary

This article suggests that DNA methylation is a mechanism that is dependent on external experiences and changes gene function and phenotype in a stable way. These reactions are visible throughout the system and not just in the brain, since social distress has important physical consequences. Because it can affect the entire system, DNA methylation has important practical consequences.