With the recent devastating discovery of 215 children in unmarked graves at a former residential school in Kamloops, B.C., in Canada, the pain and fear of First Nations communities has hit front page media again. I say it this way because, in talking with individuals from First Nations communities the trauma of both first hand experiences and those of friends and family members is not something that is ever absent for those within First Nations communities. And, it turns out that this trauma is likely written across generations in people’s DNA.
Daskalakis et al (202l) examined gene expression in individuals who were children of Holocaust survivors compared to adult children of Jewish parents who were not exposed to the Holocaust. Past studies had found that offspring of Holocaust survivors, as well as Cambodian and Rwandan genocides show more symptoms of anxiety, depression, and PTSD when other factors were controlled for.
What is gene expression? Gene expression is how cells will use DNA as the instructions for making different molecules. While the DNA codes the instructions other factors, called epigenetics, such as molecules attached to the DNA affect how many, if any, of a particular molecule will be made. You could think of it as flipping through a physical recipe book. Some recipes may get made a lot and others not all and this can be impacted by things stuck on the book like a sticky note to mark a page or a bit of stray batter that sticks the pages together. These can be passed onto the next generation with the recipe book.
Daskalakis et al found that there are distinct epigenetic changes associated with the offspring of Holocaust survivors. In total, they found 42 different gene expressions, most of which have previously been associated with intergenerational stress effects like famine. The sex and age of the exposed parent, as well as parental PTSD all impacted these changes in gene expression, sometimes in opposite directions.
More research, with larger sample sizes, and covering more atrocities would be beneficial from a scientific perspective. However, on a human perspective no one should need biological evidence of the harm torture like the Holocaust or residential schools caused intergenerationally. But perhaps, in learning more about the extent of the harm one group of humans caused to another, we can make strides towards reconciliation and the prevention of future atrocities.