The study of epigenetics has changed how we look at the effect that our genetic inheritance has on our physical and mental health, as well as on that of our children and grandchildren.
Research done by Moshe Szyf, a pioneer in this field, suggests that biochemical signals that pass from mothers to offspring prepare the child for the environmental and social conditions of their world.
This is done not by altering the sequence of DNA, which is fixed and very hard to change. Instead, epigenetic modifications, or “tags,” help determine which genes are active and when. This is crucial to normal development, but these tags also affect how organisms interact with their environment.
In this TEDx talk, Szyf describes research done in rats and monkeys which shows that the conditions of an animal’s early life may lead to certain epigenetic modifications. These changes can have dramatic effects on the animal’s later physical and mental health.
Other studies show that the same processes occur in people. Research looking at children born to mothers who were pregnant during a natural disaster found that stress experienced by the mothers reprogrammed the genes of their child through epigenetic tags.
Szyf points out that epigenetic modifications are not good or bad. They are simply a genetic way of preparing a child for their future environment, whether that means living in a country with low light during the winter, dealing with scarce food or facing high stress.
Although the epigenetic preparations that we inherit from our mothers are often useful, they can sometimes be maladaptive. For example, tags that were supposed to prepare us for famine may encourage us to eat high-calorie fast foods and cause our body to store it as fat. This can lead to obesity, cardiovascular problems and metabolic disease.
Epigenetics also opens up the door to overcoming these adaptations. Other research described by Szyf shows that it may be possible to reprogram the epigenetic layer, to wipe away the tags that contribute to metabolic disease, addiction or mental health problems. So while our DNA sequence is largely fixed, we have some freedom to alter how it functions in our bodies.