Violence during childhood would have an even greater impact on the victims than was previously thought.
Violent episodes during childhood would leave stigmas on the DNA, according to a new study, and could influence several generations. We are talking here about physical, psychological and sexual aggression. “We looked at the association between childhood abuse and methylation of DNA in human sperm,” the researchers say. Methylation is a chemical modification that can be positioned at millions of locations on the DNA sequence.
Their study has shown that paternal environmental stressors can affect sperm DNA methylation and gene expression in offspring. “Child abuse has been associated with epigenetic markings in human blood, saliva and brain tissue, and statistically significant differences in methylation vary widely,” say the scientists.
To reach these conclusions, the team analyzed sperm samples from 34 men. 22 of them had been abused as children. Twelve regions of DNA differentially methylated by childhood abuse were identified. They were responsible for neuronal function (MAPT, CLU), fat cell regulation (PRDM16), and immune function (SDK1).
Given the significant impact of child abuse on the sperm of the victims, the offspring of those exposed to violence during childhood are at a higher risk of having physical and neurological health concerns throughout their lives. In concrete terms, “trauma affects the behavior of the victim, some become depressed or become subject to post-traumatic stress,” says scientist Andrea Roberts, director of the study. “Early stressors affect sperm and, by extension, the health of the offspring, particularly by creating anxious behavior.”
The impact of such a discovery could also be legal. “Methylation is starting to be seen as a potentially useful tool in criminal investigations – for example, by providing investigators with the approximate age of someone who has left a trace of their DNA,” says co-author Michael Kobor.