Research linking trauma in one generation to epigenetic effects that influence subsequent generations may be overstated, the New York Times reports.
Earlier this year, researchers from Leiden University Medical Center examined the epigenomes of individuals whose mothers were pregnant with them during Dutch Hunger Winter of 1944 to 1945. They reported in Science Advances that these individuals had higher rates of obesity and other conditions, as compared to their unaffected siblings. They also found that individuals exposed to famine in utero had particular methylation tags, including ones near BMI-linked genes.
Other studies have also linked trauma endured by one generation to effects on their children and even grandchildren, the Times says, but critics tell it the evidence isn't strong enough to make any conclusions. One issue, it notes, is that how the epigenetic marks are transmitted — especially as epigenetic marks are typically reset after conception — isn't clear, though some animal studies have suggested possible mechanisms.
"The idea that we carry some biological trace of our ancestors' pain has a strong emotional appeal," the Times writes. It adds that "for now, and for many scientists, the research in epigenetics falls well short of demonstrating that past human cruelties affect our physiology today, in any predictable or consistent way."