Invisible imprints

A research titled, “Parental olfactory experience influences behavior and neural structure in subsequent generations”, done in 2013 by Brian G. Dias and Kerry J. Ressler, investigates how different environmental factors, experiences or smells one generation is exposed to can have a long-lasting effect on the behaviors and neural development of its offspring.

This is evidence of transgenerational epigenetic inheritance, meaning the idea that something your ancestor experienced leaves tiny “post-it notes” on the DNA. These notes change nothing in the genetic code itself; they are just instructions, and they are passed down to the offspring, influencing how the body or brain reacts to particular things.

These researchers conducted a study on mice to see if a parent’s experiences with certain smells could affect their children. Here’s what they did:

• They exposed adult mice to a specific scent and paired it with a mild shock, teaching the mice to associate that smell with danger.

• Later, the researchers looked at the offspring of these mice, even though the young mice had never been exposed to that smell or experienced the shocks themselves.

• The offspring were more sensitive to the same smell their parents had learned to associate with danger. Their brains also showed changes in the areas that process smells, making them more alert to it.

• The researchers found evidence that this sensitivity was passed through changes in the sperm or eggs of the parent mice not through DNA itself, but through chemical markers (epigenetic changes) that influence how genes work.

Abstract of this research states:

"Using olfactory molecular specificity, we examined the inheritance of parental traumatic exposure, a phenomenon that has been frequently observed, but not understood. We subjected F0 mice to odor fear conditioning before conception and found that subsequently conceived F1 and F2 generations had an increased behavioral sensitivity to the F0-conditioned odor, but not to other odors. When an odor (acetophenone) that activates a known odorant receptor (Olfr151) was used to condition F0 mice, the behavioral sensitivity of the F1 and F2 generations to acetophenone was complemented by an enhanced neuroanatomical representation of the Olfr151 pathway. Bisulfite sequencing of sperm DNA from conditioned F0 males and F1 naive offspring revealed CpG hypomethylation in the Olfr151 gene. In addition, in vitro fertilization, F2 inheritance and cross-fostering revealed that these transgenerational effects are inherited via parental gametes. Our findings provide a framework for addressing how environmental information may be inherited transgenerationally at behavioral, neuroanatomical and epigenetic levels."

I’m leaving this song here as well:

Just some food for thought.