It is a truth universally acknowledged that being a human can be stressful. Whether it comes from an unfulfilled desire for a more flexible workplace, ill health, or family tension, none of us is immune to the physical and mental effects of stress.
Unfortunately, there seems to be an increasing amount of evidence that the effects of your stress might not end with you. Stressors you experience may actually result in changes to the expression of your genetic code, which then can be passed down to your offspring. While recent research, on humans and animals, has been controversial because it calls into question the strict definition of what is “inheritable,” it has also been galvanizing. A brand new study published in the journal Science Advances last month has now traced (in worms) how these epigenetic changes can show up in offspring five generations down the line.
“How and why these changes are transmitted between generations is what [lead author Ben] Lehner and his colleagues [at the Barcelona-based Centre for Genomic Regulation] were interested in studying. In their worm study, they inserted a gene into the worm genome that would normally be silenced, and found the worms with the gene also carried mutations in proteins involved in the copying of DNA. Their offspring did not carry the same mutation in DNA replication, but for the next five generations the gene in question was still incorrectly activated.”
How this happens is not yet fully understood by researchers, but, in humans, it could point to a method for a community to respond to stresses like famine, in a way that pivots faster than the traditional Darwinian concept of evolution. In fact, to a lot of folks, epigenetics is looking more and more like Lamarckian heredity – the now rejected theory that “soft” personal traits acquired over an organism’s lifetime can be passed down, not just “hard” genetics (Jean-Baptiste Lamarck’s classic example was the long neck of the giraffe – lengthened over time by each generation’s stretching to reach and eat the topmost leaves on trees.)
This research could someday allow us to help people with conditions that otherwise seem mysterious in origin – for example: young children with severe depression, that may actually result from experiences their mothers had before they were born; or diabetes and shortened lifespan in men whose fathers or grandfathers lived through a nutritional boomjust before puberty.
While the relationship between epigenetics and evolution is uncertain, it certainly can’t hurt to try to reduce your own stress levels. Not only will you feel better, but science may one day show you’ve helped your great-great-great-grandkids as well. Until then – we’ll keep exploring!