Epigenetic Memories May Be Passed Down for Up To 14 Generations

For several decades, the popular belief was that everything about our health and even our nature as individuals was controlled by our DNA. This century, fortunately, the effect of our environment on gene expression, known as epigenetics, is becoming more widely known and understood. The epigenetic changes to our gene expression can even be passed down generations, and new research has found that this effect can be stronger than we thought.

To see how long epigenetic changes may be able to hang around in an animal's DNA, researchers genetically altered worms to carry a protein that made them glow under ultraviolet light. Then, they put them in containers with different temperatures to see what effects heat or cold had on their ability to glow. Worms in the container that was constantly 20 degrees Celsius barely glowed, as this temperature decreased the expression of their new gene. When they were moved to a container that was 25 degrees, the gene was much more active and they glowed brighter.

We have power over our health!

The usual expectation would be that once the worms were put back into the cooler container, they stopped glowing so much. However, they continued to glow, likely meaning that their genes kept a "memory" of the warmer temperatures. This persisted for seven generations, even though these worms never experienced the warm climate. The researchers then kept worms in the warmer container for five generations and transferred the next set of offspring to the cooler one. Their glowing gene was able to persist for fourteen generations - the longest time that scientists have ever documented the passing down of epigenetic changes! While these worms do have a very short lifespan, and 14 generations only took 50 days, this brings us another step closer to understanding epigenetics in all animals, including humans, and how we can use it to our benefit.

This phenomenon has already been documented in humans. Rachel Yehuda, whose specialty is the inter-generation effects of trauma, studied the effects of living through the Holocaust on survivors and their children. Among both survivors and children, stress hormone profiles were different to your average person. Both generations had low levels of cortisol, a stress hormone which helps you recover from trauma, especially in children whose mothers had PTSD. The children had higher than usual levels of an enzyme which breaks down cortisol. These changes may be intended to protect against the harmful effects of chronically high cortisol. The mind has powerful effects on our physical health, as demonstrated in research on meditation where the practice has even been found to make our cells younger. In conclusion, genes are not destiny. We have power over our health, but if we choose to have children, we must keep the health of future generations in mind.