Your Fears May Not Be Your Own

It seems that it’s not just physical traits that are inheritable. Now scientists are finding evidence that learned behaviors and even phobias can be passed down through the generations via chemical changes in the DNA.

Research conducted with mice – at Emory University’s School of Medicine – demonstrated that a stressful event experienced prior to breeding created offspring with the same conditioned response to the stressor. In this case, it was a fear of the smell of cherry blossoms, which the parents were exposed to at the same time as receiving an electric shock. The next generation exhibited a fearful response when the smell of cherry blossoms was introduced – as opposed to a fragrance that carried no historic negative charge. The phobia continued on down the generations, even if the mice were bred through artificial insemination,

Structural changes in the brains of the exposed mice and their offspring showed up in the areas of the brain used to detect odor. There were also chemical changes in their DNA – known as ‘epigenetic methylation’ – on the gene responsible for detecting odor, suggesting that the experience of the stress travels from brain to genome in ways scientists do not yet understand. That will be the subject of further research.

Whether human genes also carry ancestral ‘memory’ of traumatic events is as yet unknown. However, Professor Marcus Pembry, a geneticist at University College London, cited the “compelling evidence” for the biological transmission of memory. He suggests, “we will not understand the rise in neuropsychiatric disorders or obesity, diabetes and metabolic disruptions generally without taking a multigenerational approach.” The results of the study were published in the journal Nature Neuroscience.