Children of Holocaust survivors may have been indirectly traumatized by the event due to genes passed from their parents, a remarkable new study has found. New finding is clear example in humans of the theory of epigenetic inheritance: a idea asserting that environmental influences like smoking, weight loss and pressure could affect the genes of one's children and even grandchildren.

The research, which was published in the journal Biological Psychiatry, included 32 test subjects, Jewish men and women who were at concentration camps during the Holocaust.  Children of Holocaust survivors were found to be three times more likely to develop post-traumatic stress disorder if they were exposed to a traumatic event than demographically similar Jewish people whose parents did not survive the Holocaust.

The team were specifically interested in one region of a gene associated with the regulation of stress hormones, which is known to be affected by trauma. Researchers found that children of Holocaust survivors had the same neuroendocrine or hormonal abnormalities that the Holocaust survivors and other people suffering from post-traumatic stress disorder had.

It led them to the conclusion that specific risk for certain things, like post-traumatic stress disorder, was associated with having a parent that had post-traumatic stress disorder. “The gene changes in the children could only be attributed to Holocaust exposure in the parents," Dr. Rachel Yehuda, who led the study, determined.

 While the scientific convention is that only genes that are included in one's DNA could transmit biological information from one generation to the next, genes do change based on the environment on a regular basis, through chemical marks that attach themselves onto one's DNA.

 It’s still not clear how these tags might be passed from parent to child. Genetic information in sperm and eggs is not supposed to be affected by the environment – any epigenetic tags on DNA had been thought to be wiped clean soon after fertilization occurs.

However, research by Azim Surani at Cambridge University and colleagues, has recently shown that some epigenetic tags escape the cleaning process at fertilization, slipping through the net.


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