In what is being called the first evidence found in humans to support the theory of epigenetic inheritance, researchers from New York’s Mount Sinai hospital have found that the traumatic events experienced by Holocaust survivors were passed on to their children.
In the study, which was published in the journal Biological Psychiatry, Dr. Rachel Yehuda and her colleagues looked at 32 Jewish men and women who were either interned in a concentration camp during World War II, or who had witnessed or experienced torture from the Nazis.
They also looked at the DNA of 22 of their adult offspring, as well as demographically similar parents and offspring, and found genetic changes in the children of Holocaust survivors that they claim could only be attributed to their parents’ traumatic experiences during the war.
According to the UK newspaper The Guardian, the new study is the first example of epigentic inheritance (the idea that environmental factors can alter the genes of offspring) in humans, and is a clear sign that the life experiences of a person have an impact on future generations.
Epigenetic tags found in stress-related genes
In the study, Dr. Yehuda and her co-authors focused on measuring cytosine methylation within the gene encoding for FK506-binding-protein-5 (FKBP5) for the participants, and learned that Holocaust exposure and an effect on FKBP5 methylation that had been observed in both exposed parents and their offspring. It was higher than normal in survivors and lower in their offspring.
The results were compared with Jewish families who were not living in Europe during the war, and concluded that the DNA changes found in the children could only be attributed to Holocaust exposure in the parents. The authors called the results “the first demonstration of transmission of pre-conception parental trauma to child associated with epigenetic changes in both generations.”
The gene at the center of the study is one associated with the regulation of stress hormones and is known to be affected by trauma, The Guardian said. Dr. Yehuda explained to the newspaper that it “makes sense to look at this gene,” because if there is “a transmitted effect of trauma,” it would likely be found in “a stress-related gene that shapes the way we cope with our environment.”
Epigenetic tags were found on the same part of the gene in both Holocaust survivors and their offspring, but not in any members of the control group, and additional genetic analysis allowed the researchers to rule out any changes due to trauma experienced by the offspring themselves. The causes of this parent-to-child transmission are still not known, the authors noted.
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