Are you afraid of spiders? Can you think of a solid reason, or experience that made you afraid in the first place? If not, it could mean that you have genetically inherited that phobia from your ancestors, who could have had a traumatic experience with arachnids.
Common knowledge is that memories and learned experiences through one’s lifetime are passed down by teaching future generations or through personal experience. However, new research suggests that certain information may be transferred through the genes.
According to researchers at Emory University School of Medicine, Atlanta, the genetic transfer of memories occurs as a result in change of the chemical makeup of the genes which happens during certain experience. In particular, the results from the study show that traumatic experiences can be genetically passed down to future generations.
In this study, researchers trained mice to fear the smell of cherry blossoms. Before allowing them to reproduce, they conditioned the mice to be traumatized by the smell of cherry blossoms by using electric shocks.
After the mice reproduced, their offspring were exposed to the smell of cherry blossoms, and surprisingly, they showed fearful responses to the smell, although no such experience was actually present in their lifetime. Which is even more curious, the same response could be seen in the following generation too.
During the conditioning process, the brains of the group exposed to the shock showed structural and chemical change in the area that detected the odor, which the offspring and the third generation exhibited as well. Not only did their brain change, but the DNA of the mice had changed too.
To make sure that this phobia was not a social transmission, the scientists inseminated some of the females through IVF. When they saw that the change in the brain structure persisted, they concluded that the brain anatomy was not socially conditioned, but rather inherited.
The resulting phobia in the future generations was inherited through the DNA, which shows how the reactions of these generations were already programmed, perhaps to protect them from the experience which proved to put their ancestors in danger.
The results of the study gave “compelling evidence” that biological transmission of memory is possible, said Professor Marcus Pembrey, a pediatric geneticist at University College London. He added that this addressed constitutional fearfulness that was highly relevant to phobias, anxiety and PTSD, plus the controversial subject of transmission of the ‘memory’ of ancestral experience down the generations.
The implications of the finds can be huge when it comes to human behavior, especially in understanding the rise of neuropsychiatric disorders or obesity, diabetes and metabolic disruptions among humans by taking a multigenerational approach, notes Marcus.
Research like this may prove to be crucial in understanding certain things about the human mind, and what makes us who we are. It could prove beneficial in enhancing treatments for certain illnesses and provide better treatment altogether.
The notion that our DNA could be carrying lessons learned from our ancestors is quite interesting in itself. Perhaps we relive the history of our ancestors without knowing it?