How does a baby bird know to act like a poisonous worm when a predator shows up? The answer is genetic memory, but how does it work? How does it get encoded into dna, passed down, and executed.
In: Biology
This is something pretty difficult to ELI5 because the answer involves a lot between DNA and behavior and a lot of that is not well characterized. Every answer is bound to be fairly badly incorrect (for instance, those asserting that it is NOT memory are probably, to some degree, incorrect – and, in fact, contrary to what we were all taught – Lamarck was not entirely wrong either).
Some DNA is transcribed into RNA which is translated into proteins. Not all DNA is used to encode proteins.
DNA, RNA, and proteins all control when and how much any given protein is produced. The when is important. Producing certain proteins at specific times can determine what kind of cell the cell is.
When birds (or people or dogs or any complex multicellular organism) are developing from a single cell protein expression for various cells are turned on and off. This varied protein expression allows different kinds of cells to be produced from a single cell (the bird egg).
Some of those cells are brain cells.
Differential expression of proteins also produces architecture in the brain of the bird. The bird’s brain is not homogeneous with every cell and its interactions with other cells identical.
Some connections between some cells in the brain are, in fact, determining the observed behavior. Those connections were formed early in the bird’s life and were most likely created by differential expression of proteins.
It is NOT certain at all that the differential expression of the proteins that leads to the brain architecture storing the behavior is directly encoded in the DNA. Some part of it likely is and some part likely is not. Some part may have arisen through mutation and some part may have arisen through what used to be called Lamarkian evolution – and now is called epigenetics.
That’s all probably not ELI5 but what you are asking is simply not fully characterized. My suspicion is that you are, in fact, correct to call it memory because I suspect that when neuroscience fully characterizes complex brains we will find that memory and innate behavior are not nearly as different as some assert. They are almost certainly not the same but IMO they share many similar and some identical methods of encoding.
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