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
The phenomenon described in the article is just a fancy way of saying that organisms with a nervous system tend to have basic “instincts”. So, really the question is how instincts like wanting sex, or looking for certain flowers in bees, can be passed down within a species.
The short answer is that a brain is a machine that has the interesting property that its “wiring” will change its behaviour. In some parts of the brain the wiring may be protected from changing a lot, while in other parts of the brain the wiring can change quite easily and quickly. The wiring that is protected from change is how “instincts” are encoded, babies are simply born with it because their genetic code from their parents has pre-encoded their brain with this wiring. For example, equestrian animals like horses can be up and walking around minutes after their birth because their brains already contain all the wiring they need to understand how to do this, a really useful adaptation for a wild animal that needs to run away from predators!
The wiring that is allowed to change is how brains are able to “learn” from “experience”. Most parts of the brain can change a little bit, and in “smart” animals it is typically the case that change is easier or that the amount of tissue that holds the wiring is greater. Humans have brains that are both very good at changing and also contain a lot of the tissues that contain the wiring, so we have a huge advantage over other animals.
As to how the pre-wiring can be passed down genetically, well that is a very similar question to how any part of the body gets passed down. The pre-wiring is a physical aspect, just like having arms or having hair in one place instead of another. The same genetic mechanisms that encode these important physical parts of your body also encode the physical layouts of the wiring in the brain that create instincts.
EDIT: I see from some other posts that maybe you’re asking about Epigenetics? This is a little different from instinct in that it’s more like a “temporary” genetic memory. In short, your genetic blue print can be though of like a drawing of a building. The drawing tells the workers how to build the building. Epigenetics is like footnotes in the margins that get added over your life time as the builders have to try to overcome realities in your life. For example, starvation can cause your body to add epigenetic markers in your DNA that alter it to increase the production of certain chemicals that help you to survive starvation. Recent studies have suggested that a baby forming in the mothers womb can maybe inherit some of these “footnotes” into their own DNA as they are forming. This is a way for the mother to directly pass down some useful information to her baby because if the mother is starving a lot, then it’s probably useful for the baby to have DNA that is already prepared for that.
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