Epigenetic’s & Transgenerational Trauma (Part II)

While the thought of inheriting trauma seems absurd, there is scientific evidence of its possibility. Exposure to trauma does not trigger mutation, but it does affect gene expression – this is called epigenetics. Epigenetics is the study of how the environment and behaviors influence gene expression. Having this trauma-induced inherited gene expression means you can relive your parents’ and grandparents’ trauma. The genes raise your sensitivity to stress, stress response, or enhance your resilience to stress.

Epigenetic changes do not alter the DNA sequence. They only interfere with the phenotypic expression of the genome. In other words, the body misinterprets the coded gene sequence of a protein, causing it to produce a different protein – this alteration occurs in patients with post-traumatic stress disorder (PTSD). It is also prevalent in people constantly exposed to stressful situations.

For the longest time, it was theorized that only environmental and behavioral factors contributed to trauma. Presently, there is an emerging body of evidence that trauma can be passed to progeny through epigenetic mechanisms – particularly in DNA methylation.

Epigenetics also influence gene expression through histone modification – DNA wraps around histones (proteins), rendering them unavailable for RNA to read the DNA gene sequence. Additionally, epigenetics regulates gene expression by increasing the activity of the Non-Coding RNA. The Non-Coding RNA attaches to the Coding RNA, responsible for making proteins, inhibiting its activity. It also recruits proteins that modify histones which turn genes ‘on’ or ‘off.’

DNA Methylation and Psychological Disorders

In DNA methylation, a methyl group (R-CH3) is added to the C5 position of the cytosine of a DNA molecule, producing a 5-methylcytosine. The inclusion of this molecule changes the activity of the DNA without affecting its sequence. The effect of the methylation also depends on the area of methylation.

Typical consequences of methylation include gene expression suppression, tissue-specific gene expression control, and genetic imprinting. For instance, gene suppression occurs when the methylation occurs in the promoter region of the DNA molecule. The outcome of this suppression is vulnerability to depression and suicidal ideation. The alteration is identified as a chemical marker or epigenetic signature.

Evidence of Transgenerational Inheritance of Epigenetic Induced Trauma

The transgenerational nature of epigenetics gained interest because of evidence of the presence of chemical markers in the fetus of pregnant women during the dutch famine that occurred at the end of the second world war. Similarly, epigenetic signatures were identified in the progeny of Holocaust survivors. The result of these chemical marks was a vulnerability to stress or increased resilience.

Another study looking into the effect of the war in the Congo and transgenerational trauma revealed that there was increased expression of the glucocorticoid receptor NR3C1 induced by methylation activity in newborns. The overexpression of this receptor increased their sensitivity to stress and reduced resilience. It also increased their vulnerability to disease later in life. Similarly, a study on lab rats raised in a distressful environment showed alterations in their neurodevelopment. The epigenetic modifications which affected the rats’ response to stress was passed to the rats’ progeny.

Historic Trauma has a long history and can be transcended through generations biologically and we must continue to evolve our research in this area.