Abuse Marks DNA


People who were sexually abused as children often carry emotional scars into adulthood. But now a study shows that it even leaves genetic scars, meaning that regions of the DNA are marked. So, it's possible one day tests can verify a victim's story. So what do we mean when we say their DNA is 'marked'?

We're talking about epigenetics. See, there are elements in DNA that regulate when and how much of a gene's products will be made. An even finer layer that also controls gene usage is what we call epigenetics.

Epigenetic changes result from the addition of methyl groups which consists of one carbon and three hydrogen molecules to bases of DNA. This reduces the usage of a gene just like a dimmer switch on a light. It dims gene expression. The environment influences where and how many of such epigenetic marks are added to DNA.

Exposure to physical or mental trauma, starvation, toxins, and smoking can all cause those changes. Studies show childhood sexual abuse causes epigenetic changes in blood, saliva and brain. A more recent study also found these changes in sperm, making us believe the changes are inheritable.

The study involved forty six sperm samples from thirty-four men who reported either no abuse, medium or high abuse. For men who reported being abused, eight regions of DNA were dimmed by more than ten percent and twenty-nine percent in one region compared to unabused men.

The study had a small sample size so this needs a lot more work but it's a powerful statement about the legacy of child abuse and may one day provide proof for the support these kids need.

More Information

Exposure to childhood abuse is associated with human sperm DNA methylation
Offspring of persons exposed to childhood abuse are at higher risk of neurodevelopmental and physical health disparities across the life course. Animal experiments have indicated that paternal environmental stressors can affect sperm DNA methylation and gene expression in an offspring...

Child sex abuse may leave 'molecular scars' on DNA which could be used as evidence in court, new study finds
Childhood sexual abuse may leave 'molecular scars' on a victim's DNA which could one day be used as evidence in court, scientists have said. A new study found similar alterations in the activity of genes among men who had been abused in childhood...

Epigenetics: Fundamentals
Epigenetics is the study of heritable changes in gene expression (active versus inactive genes) that do not involve changes to the underlying DNA sequence ' a change in phenotype without a change in genotype ' which in turn affects how cells read the genes...