A study on Holocaust survivors finds that they could have passed on trauma to their children's genes. Researchers at New York's Mount Sinai hospital claim that this could be some of the first concrete evidence that a person's life experiences can be passed on to subsequent generations.
The study, carried out on 32 Jewish men and women, found that trauma suffered in their lifetime could have influenced changes in their DNA that affects their children. They found an increased likelihood of stress disorders, and compared the results to Jewish families that were not in Europe during the war.
Rachel Yahuda, director of the Traumatic Stress Studies Division, who leads the research team concludes that there was enough evidence to show that trauma can be transmitted to children through "epigenetic inheritance". This is when person's experiences affect the genes passed onto their offspring.
"The gene changes in the children could only be attributed to Holocaust exposure in the parents," Yehuda said. She noted that survivors' children are more likely to develop stress-related disorders compared to those in Jewish families who were living outside Europe during the Second World War.
Yehuda's team examined a specific gene that monitors the regulation of stress hormones, known to be affected by traumatic experience. The researchers discovered epigenetic tags in the same part of the gene for both Holocaust survivors and their children, which were not found in any of the control group.
"It made sense to look at this gene," said Yehuda. "If there's a transmitted effect of trauma, it would be in a stress-related gene that shapes the way we cope with our environment," she explains. "This provides the first demonstration of transmission of pre-conception stress effects resulting in epigenetic changes in both the exposed parents and their offspring in humans," Yehuda said.
If a person's epigenetic tags – chemicals that attach to DNA and turn specific genes on and off – also appear in an individual's children, it means that a parent's smoking, diet and stressful events could affect their children's health. The idea of epigenetic inheritance remains controversial. But this study's findings suggests that DNA is not the only way to transfer biological information between generations.