The term “epigenetics” has been making headlines left and right in the scientific and healthcare communities. If you’re unfamiliar with the concept, the term literally translates to “above genetics” — meaning that the observable traits or characteristics in an organism are changed without any actual rewrites to the organism’s genetic code. Before epigenetics, it was thought that the only method to change a trait was to alter the related DNA sequence. Now, studies are showing that this isn’t the only way.
How Does It Work?
There are several types of epigenetic modifications. One is methylation. When a chemical group known as methyl is added to a strand of DNA, it can either prevent or allow certain gene expressions, much like flipping an on/off switch. Another type of epigenetic change is histone modification. In histone modification, strands of DNA are wrapped around proteins called histones, which act as a spool.
Your behaviors, choices and exposures throughout your lifetime can change how tightly the strands of DNA are wrapped around the histone spool. The tighter they’re wrapped, the harder it is for the DNA to be read, while more loosely wrapped strands of DNA allow the genes to be read more easily. A gene that can be read can be expressed as an observable trait or characteristic, such as brown hair color or type A blood.
Not sure what we mean? Consider your genetic makeup as a book. The pages represent chromosomes, the sentences are your DNA, and the words are your genes. Epigenetics could be viewed as the punctuation. Punctuation doesn’t rewrite the book, but it can affect the meanings of specific sentences and the emphasis placed on certain words.
A large part of epigenetics focuses on ways that your decisions, behaviors and exposures can affect you and your descendants’ DNA. No matter what type of epigenetic modification occurs in your DNA, if parts of your genes are turned on or off, these changes will occur in every piece of DNA in every cell in your body, including your reproductive cells.
This way, even if you’re not pregnant or even if you’re male, you can pass these gene changes to your offspring since every child inherits half its DNA from the mother and half from the father. Epigenetics is also useful in explaining why identical twins can grow up to be different from each other. While they may have the same genetic makeup, their lifestyles and experiences can turn on and off affected genes, making them turn out very differently.
Examples of Epigenetics
Many experimental studies have shown the effects of epigenetic changes. One of the more well known studies observed the amount of nurturing rat pups received from their mothers in the first few weeks of their lives. Rat pups who had more attentive mothers grew up to be more relaxed adults while pups raised with mothers who didn’t spend much time grooming and caring for them developed into anxious adults. The care level of the mothers turned “on” or “off” the expression of pathways in the rats’ brains that dealt with stress, allowing the nurtured rat pups to calm faster after a stressful situation. Though the mother’s behavior affected the epigenome of the pup early in development, this change lasted the rest of the rat’s life.
A study from the Journal of Molecular Psychiatry found that mothers who experienced major depression were more likely to have daughters and granddaughters who also had depression. This finding is supported by another study published in the Journal of Biological Psychiatry, which found that Holocaust survivors had epigenetic changes in areas of the brain that deal with trauma. Interestingly enough, these epigenetic changes were also found in the survivors’ children even though they hadn’t lived through the same horrors as their parents.
In a study done at Emory University in Atlanta, mice exposed to the pleasant smell of a flower were given a small electrical shock at the same time. Eventually, this caused the mice to fear the flower smell because it made them anticipate the shock. When these mice reproduced, researchers observed that the next two generations of mice were also fearful of the flower smell even though they had never been exposed to the shock stimulus. This was likely due to an epigenetic change in the parent mice that had been passed down.
What Can You Do?
On a lighter note, studies have also found that making healthy lifestyle choices can become part of your generational epigenome as well. Healthy diet, regular exercise and avoiding alcohol, cigarettes, stress and harmful toxins can help regulate normal methylation, making your genes and possibly the genes of your offspring more resistant to diseases like cancer (which can be caused by unregulated DNA methylation).
If you want to play it on the safe side and promote longevity in yourself and your descendants, it’s best to listen to what your doctors have been saying all along: Eat healthy and make smarter lifestyle choices.
Although epigenetics is a new field, its findings are already reinforcing the importance of diet, exercise and stress management. Scientists hope to eventually be able to use medicine to turn on and off epigenetic tags, allowing the prevention and treatment of many types of diseases.