Understanding Epigenetics

By Molly O'Brien

By Molly O’Brien

Epigenetics is one of the largest waves of research to hit the scene since the discovery of DNA structure in the early 1950s. Watson and Crick’s breakthrough in the mid-20th century lead to unparalleled discoveries concerning how our genetic makeup is fixed through inheritance. Today, scientists are learning this is not entirely true. There are other forces acting upon our genes that determine which genes are turned “on” or “off” and the degree to which traits are expressed. Environment, stress and lifestyle choices are all influences being studied as potential gene changers.

According to the journal Environmental Health Perspectives, the word “epigenetics” literally means “in addition to changes in genetic sequence.” The field studies any process that acts upon genes and alters their activity without actually changing DNA arrangement. Two heavily studied epigenetic processes are methylation and chromatin modification. Methylation creates changes in gene expression through the addition or removal of a methyl group (a small packet of carbon and hydrogens) on a segment of DNA. The methyl group acts like an “on” and “off’ switch for the gene. Chromatin modification has to do with how tightly genetic material (chromatin) is coiled inside a cell. Proteins called histones are responsible for keeping genes properly bundled. When their structure gets altered, genetic expression is altered as well. In general, tightly folded chromatin is turned “off” or on “low,” and loosely bundled chromatin is turned “on” or functional.

It has been well established that certain behaviors pose a threat to health. For example, smoking can cause cancer. We do not question that truth. But epigenetics takes this concept further, positing that an array of life choices, upbringing and even socioeconomic status can actually change the way our genes are expressed. Furthermore, these genetic changes we create through our choices are inheritable and can be passed down through generations. Plainly put, your grandfather’s life choices may be reflected in the way your genes get expressed. While this is startling information to swallow, it also holds immense promise. The idea that we, as individuals, have the ability to alter how our genes are expressed is a powerful notion. Genetics is no longer a fixed, immutable code that we are subjected to, but rather a blueprint that we can edit through our choices and actions.

Although research is still in its nascent stages, the evidence that supports the effect lifestyle choices have on gene expression is quickly mounting. A study published in the Proceedings of the National Academy of Sciences illuminated the effect insufficient sleep has on gene expression. After one week of insufficient sleep, researchers found that participants had 711 genes that were “up- or down- regulated” due to lack of sleep. The genes affected played important roles in chromatin remodeling, gene regulation and immune and stress responses. Similar studies are being conducted to learn more about how factors such and stress, diet, etc. play a role in altering gene expression.