The Wikipedia page is very short: https://en.wikipedia.org/wiki/Genetic_memory_(psychology)
And it refers to a Lamarckian process? The linked article is a little bit woolly. Are there any known studies definitively showing that genetic memory is encoded in DNA? What can be encoded? How much?
In: Biology
You’ve stumbled upon a highly complex topic that practically remains entirely unknown. I don’t like the term genetic memory, it’s too vague and inaccurate.
It’s going to be quite difficult to explain this, I have to find a balance between sacrificing brevity for clarity and sacrificing clarity for maintaining reader interest that would easily be lost if the comment is a thesis.
I take it you understand the concept of genetics. Your DNA has a 4 letter alphabet, it is stable and protected, carried from generation to generation, vertically transmitted. It’s the blueprint for the majority of what you are at the biological level. But that’s not all, there is something called epigenetics. It’s a modification that doesn’t alter this alphabet yet affects it in a way that can, but doesn’t always, get carried vertically (to progeny). To give a concrete example that aids in understanding, DNA is highly dense due to its enormous size, and to be compact, it is wrapped around proteins and then that is coiled further and further. Eventually you have an ultra dense chromsome that leaves no place for the reading/transcribing machinery to be recruited such that the information can be turned to product. To read a specific part of the DNA, the cell needs to slightly loosen the region of interest, exposing regions with codes that recruit this machinery. Epigenetic modifications can be on the proteins the DNA is wrapped on (making them tighter or looser or completely sealed away) or on the DNA itself, in places like those recruitment codes, helping or preventing the recruitment.
Why do we have this system? Well it seems our cells keep showing more and more facets of their complexity, which shouldn’t come as a surprise seeing how behaviorally complex we are even though we can almost be summarized in some 800 megabytes of data. These epigenetic modifications are actually influenced by nurture (as opposed to nature), so in a more scientific lingo, it serves to link genetics to environmental factors. What’s interesting though is that, depending on the circumstances, some of these modifications can be permanent and they can reach the germ line, meaning eggs and sperms can carry them too, which means your children can be affected by things that happened in your environment.
But when discussing neuroepigenetics things are more complex. Aversive reactions for instance (fear emotions from a given concept or object) affect the neurons, so how does this get to your germ line? Well we don’t know. But we do know the timing really matters. Does it happen to the mother while you’re *in utero*? If so it can affect your germ line, which means your progeny and you can carry those modifications. This concept gets far far more complex and this is where I invoke the principle above about sacrificing clarify for reader interest. But the bottom line is that there is a lot we don’t know, but evidence shows vertical transmission of behavior can certainly happen.
If you have a scientific aptitude and would like to really dig into it, here is an absolutely brilliant paper on the topic:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4323865/
BTW, I oversimplified a lot of things about epigenetics. Keep in mind these modifications come in dozens of flavors (covalent vs otherwise for example) and affect dozens of types of targets and likely thousands of actual targets.
Edit: English
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