A genetic inheritance of trauma?
People who experience early childhood trauma, like abuse or war, often exhibit a number of hormonal imbalances. The mechanisms involved are poorly understood, but most scientists agree that traumatic events alter gene expression, which then causes misregulations in a number of biological processes. But whether these changes can actually be passed down to offspring is a controversial question, because it would imply that acquired traits – traits that aren’t actually encoded in DNA, but rather arise following certain experiences – are somehow being passed down through generations.
After the pups of the traumatized male mice were born, scientists monitored their behaviour. As expected, these pups showed the same symptoms of trauma that their fathers did, despite having never undergone traumatic events themselves. And these symptoms were even apparent in the third generation of mice. When researchers looked at the sperm of the traumatized mice, they discovered that the microRNAs in these sperm cells were also present in abnormally high numbers. “This means that germ cells – sperm in males and oocytes in females – are very sensitive to environmental conditions in early life,” Mansuy says, “and early childhood trauma has consequences not only for the brain but also for the germ cell line.”
Eva Jablonka, a molecular biologist at Israel’s Tel Aviv University who did not participate in the study, said in an email to The Verge that this study is “extremely valuable.” It gives “a more detailed mechanistic explanation of a phenomenon that for a long time was supposed to be biologically impossible,” she said. Mansuy and her team are now studying the effect of these short RNAs in humans. She notes that much more research is needed before scientists can start working on diagnostic tests or drug therapies. And, according to Jablonka, the medical community is only now becoming aware of these kinds of transgenerational effects.
Still, this study offers yet another argument for changing the way scientists approach trauma. “Epidemiological studies need to be re-thought,” Jablonka said. These effects are “enormously important” because they indicate that altering the stress condition of a child isn’t sufficient to ensure that the next generation will be ok. To achieve that result, she said, “we also have to counter the parental effects that were transmitted.”
The recognition that much more then hair colour is passed on from one generation to the next dates all the way back to Biblical times but no one has known how that took place. At least with mice, we now know and can genetically transplant the trauma into an unrelated embryo.
Obviously we can not do this order of experimentation with humans but it doesn’t take much thought to conclude we also don’t need to — or to conclude that this marks a phase change in our understanding of the impact of economic policy and social justice.
Medicating away a fractured and damaging culture and society is simply no longer an option.
To quote Isaac Asimov,
You can’t take a human being and put him to work at a job that underuses the brain and keep him working at it for decades and decades, and then say, “Well, that job isn’t there, go do something more creative.” You have beaten the creativity out of him. But if from the start children are educated into appreciating their own creativity, then probably almost all of us can be creative.