What Civil War soldiers can teach us about how trauma is passed from generation to generation

Soldiers at Petersburg during the Civil War.

that the psychological legacy of the POW camps could account for the differences. If a father’s trauma resulted in family violence, paternal absence or emotional distance, the effects would likely be seen in daughters as well as sons, they reasoned. And they weren’t.

The fact that sons, but not daughters, appeared to have inherited some lifeshortening bit of their father’s misery does suggest that a genetic actor may be at work – one that is passed along with the Y chromosome, Costa said.

Epigenetics also might be at work here, she added. That’s the chemical signaling process by which genes turn on and off in different tissues at different times, often in response to environmental factors like food supply. While epigenetic marks don’t alter a person’s genetic code, they can profoundly alter how that code is expressed. And they appear to powerfully influence the expression of genes that are passed on to a growing embryo.

Consider the evidence from a series of studies tracking several generations in the isolated Swedish community of Overkalix, Costa said. That research has linked parents’ food availability to the midlife health of their children and grandchildren. Those studies’ complex

findings have shown that dietary abundance or scarcity at specific points in time exert sharply different influences on men and women and their progeny. They’ve also furnished evidence that dietary stress may transmit certain vulnerabilities to future generations through paternal DNA.

Other studies of traumatized groups have found evidence that the experience turns genes on and off in ways that are carried down to the next generation and beyond.

In the nine months before the Allies defeated the Nazis in May 1945, Germany blocked all food supplies to the Dutch and caused a famine that killed 20,000 people in the Netherlands. Decades later, researchers would find that, in middle age, the children of Dutch women who were pregnant during that period – daughters especially – went on to suffer higher rates of heart disease, diabetes and schizophrenia. They also died earlier than their compatriots who were born before or after the famine. Six decades after their birth, the Dutch famine offspring still bore distinctive epigenetic signs of stress linked to poorer health.