Emotions play an important part in our daily lives. Fear is one such emotion that is pre-programmed into all animals and people as an instinctual response to potential danger. However, lately a new study says that mice can easily pass learned behaviors like a trained fear response to their offspring through DNA!
The researchers exposed mice to a sweet smell known as acetophenone. Then they gave those mice a small shock on their foot. The mice eventually became startled when they smelled acetophenone. After breeding the mice, the offspring were found to have the same response to acetophenone, but not other smells. Even when the populations were separated and In Vitro Fertilization (IVF) was used in place of traditional mating, the response was still present in the next two generations.
Physically, the mice have more of the neurons that are sensitive to acetophenone. Upon testing the methylation pattern of the DNA from sperm cells, researchers found increased methylation on genes that code for non-acetophenone-sensing neurons. Thus, the acetophenone-sensing genes were far more active by comparison.
Researcher Ressler said, “While the sequence of the gene encoding the receptor that responds to the odor is unchanged, the way that gene is regulated may be affected. There is some evidence that some of the generalized effects of diet and hormone changes, as well as trauma, can be transmitted epigenetically. The difference here is that the odor-sensitivity-learning process is affecting the nervous system – and apparently, reproductive cells too – in such a specific way.”
Though there are few things that researchers are still unsure about like if these effects were reversible and if it was only odors or mice can be trained to be afraid of particular sound too. Researchers have published their report in the journal Nature Neuroscience.