Of course you can. See, for example, the Lambda switch. https://en.wikipedia.org/wiki/Lambda_phage#Induction Yeast modifies its own DNA by copying one of two passive templates into an active region to switch its own internal mating state.

Viruses integrate into the human genome, then decay and eventually become fodder for new regulatory regions and genes.

During human life, your genome is mutated, and your body repairs it, sometimes making mistakes, which are permanent (and passed down to your children if it happens to the germ line).

I could go on...

Ok, DNA changes occur, but physiological writing to the DNA does not happen in humans. I'll give you DNA repair, BCR/TCR rearrangement, meiosis, and also the more recently discovered LINE-1 retrotransposons - but they occur at specific times and usually in a random fashion. I don't think this fits any idea of what memory is.

If you're saying it's theoretically possible, I would agree that it might be, and that there is a potential for DNA to be memory. But to claim that DNA is memory without a known write process is premature I think.

Yeah, I agree- you have to stretch the concept of "brain memories" pretty far to accomodate epigenetics.

For most eukaryotic organisms DNA it might not be "random access memory" but it contains a record of genes that somehow managed to get through the selective pressures they were subjected to over countless generations. I'd say that this information is an imprint of history, and is memory.

My hunch is that you're thinking of memory as being equivalent to RAM in a computer. So I'll remind you that read only memory is still memory.

Some microorganisms, like viruses, do directly modify DNA. That's where CRISPR came from.

I'd encourage you to check out the full range of definitions of the word "memory".

Read only memory was written once.

An imprint of history is not memory, in much the same way that fossils, stars, the environment is not memory. Human DNA has not been written to. It is edited in only very specific circumstances - DNA repair, TCR/BCR recombination, meiosis and interestingly, and possibly relevant - LINE-1 transposons in neural tissue.

Why not? They encode state in a way that is stable over time. Any medium that preserves state over time can and likely does function as memory in some way or another.

At any rate, DNA encodes useful information related to how an organism's ancestors were able to survive their environment. If you prefer not to call it "memory" for semantic reasons, I don't really care too much, although my opinion is that memory is too deep of a concept to be narrowly confined like that. Nevertheless, even if you don't call DNA memory, it doesn't change my point in the comments above, which is that the information encoded in DNA is directly relevant to any survival related memories, and so it would make a lot of sense if such memories were formed in direct, physical reference to that information. Seeing as how it's been shown that protein formation is involved in memory formation and recall, and seeing as RNA is how proteins get their molecular structure, it's not a far reach to see the possibility that RNA is a contextual bridge for memory to be encoded in reference to survival related information provided by DNA.

None of this requires that DNA be writable in the same way that transistor based me let is writeable. DNA is written through a probabilistic, distributed process, but it still encodes information about the molecular tools its carriers successfully managed to survive and reproduce with.