Growing up we all learn in school that we look how we look and we are the way we are largely because of our DNA – our genetics. You know, if one or both of your parents have blue eyes, you’re more likely to have blue eyes or if your family is tall, you likely will be, too. We do know, however, that our environment can affect many parts of us, as well, and can change our genetics. Most recently, scientists have discovered that our epigenetic memories can be passed down much longer than we thought – 14 consecutive generations, in fact.
Epigenetic Memories Passed Down For 14 Generations
Epigenetics is the study of how your behaviors and environment can cause change and affect the way your genes work. Germs, illnesses, and nutrition, including a mother’s nutrition while her baby is still in the womb, can affect your epigenetics. Your environment and lifestyle factors can also affect your epigenetics. These include diet, obesity, physical activity, smoking, alcohol consumption, environmental pollution, stress, and working night shifts.
These factors actually change your DNA, and these epigenetic memories then get passed on to your children. (1) Recently, scientists have discovered that these can be passed along for as many as 14 generations. This means that what your family members did 14 generations ago is affecting who you are today, and what you do can affect your successive generations for many, many years to come. (2)
For example, if your great-great-grandparents ate a diet rich in fruits and vegetables, their diet was high in antioxidants, which protect against cancer. Their bodies, therefore, became less prone to cancer. This means that their children, their grandchildren, and their great-grandchildren (aka you) could be less prone to cancer. Other factors, however, could change that. For example, say your grandfather or grandmother worked in a factory that exposed them to cancer-causing chemicals. This, too, will affect their bodies’, and their subsequent generations, ability to fight off cancer. (3)
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The researchers wanted to study how long environmental factors could leave their mark on genetic expression. For the study, they used genetically engineered nematode worms that carry a transgene for a fluorescent protein. This gene makes the worms glow under ultraviolet light when activated. They then played around a bit with the temperature of the worms’ containers, which affected how much or how little the worms glowed.
They found that the worms glowed brighter in warmer temperatures than colder, however, when they moved the worms back to the colder from the warmer temperatures, they continued to glow brightly. This means that the transgene was still highly active due to its “environmental memory”. The results only got more interesting from there.
The worms passed this environmental memory down to their offspring. For seven generations, the worms glowed brightly, despite the subsequent generations having never been exposed to warmer temperatures. Next, they kept the next five generations in warmer temperatures, after which they kept their offspring in the colder ones. In this instance, the worms continued to glow brightly for a whopping 14 generations despite having never been exposed to the warmer climate.
How Does This Affect Humans?
Naturally, just because this happened in worms, whose generational turnover is about 50 days, doesn’t necessarily mean it will replicate to the same extent in humans. For this reason, this is difficult to study in people, not to mention the vast amount of uncontrollable variables that come into play in a person’s lifetime versus a worm in a lab. That being said, there is research that shows that our environment and what we do in our lives can have an effect on that of our children and grandchildren.
There are some studies, for example, on children and grandchildren of women who survived the Irish Potato Famine that have found that these people have increased glucose intolerance in adulthood. Other studies show that descendants of Holocaust survivors have increased levels of the stress hormone cortisol in their bodies. This is the hormone that helps your body recuperate after trauma.
In more everyday scenarios, scientists are now looking at how your level of physical activity could affect the health of your children and subsequent generations’ health. Think of it as giving (or being given) a different starting line. People who are more physically active have healthier bodies – stronger hearts, more elastic veins, and the list goes on. If you are physically active, you improve these aspects of your health and then, in a way, gift those to your offspring.
Of course, if your parents and grandparents weren’t physically active, smoked, drank frequently, etc, this doesn’t mean that you are doomed. You have the power to make lifestyle changes and improve your health and that of your children. At the end of the day, regardless of your genetics, your health is largely in your hands: You can improve it or make it worse. That is up to you.
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