Epigenetic Mechanisms and Human Development

Epigenetics is the study of how an individual’s environment and behavior can modify DNA without altering the DNA sequence. These modifications regulate genes by turning genes on, increasing gene expression, or off, decreasing gene expression. Epigenetic modifications can occur through three mechanisms: histone modifications, DNA methylation, and RNA-based mechanisms.

As a quick review, the nucleus of each of the body’s cells contains DNA, the genetic material that holds the instructions, or code, for synthesizing specific proteins.

These proteins direct the function of cells which give rise to an individual’s phenotype, or their observable characteristics and traits.

The complete set of DNA instructions found in each cell is called the genome.

Okay so, to make a protein, certain genes within the genome need to be activated, or expressed. Whether a gene is expressed or not is regulated through epigenetic modifications that shape the function of the genome. Consequently, epigenetics can help explain a lot of things, like how cells in the body, such as skin cells and brain cells,

can differ from one another even though they all contain the same DNA.

It can also help explain why identical twins with the same DNA often have subtle differences in their appearance, personality, and even diseases they might develop.

Now, epigenetic modifications arise from fetal development and continue throughout an individual’s lifetime. These modifications can be the result of early experiences in life such as growing up in a nurturing environment, experiencing abuse or deprivation, and even through dietary choices, use of certain medications, or exposure to industrial pollutants.

Whatever the cause, these modifications can impact physical and mental health outcomes through their influence on DNA activity. For example, since epigenetic mechanisms can switch on or off genes involved in cell growth, like tumor-suppressor genes, they can promote uncontrolled cell growth, like with cancer. Certain cancers can also occur when genes that code for a protein that repairs DNA aren’t expressed. In contrast, the epigenetic effects of dietary folate during pregnancy can promote proper fetal development and prevent neural tube defects.