Though computers and machines DNA is quite persistent, depending on how you determine persistency. Certainly, we have found DNA at a bacterial level that is pretty much what it was a billion or more years ago. The rate at which knowledge in DNA can be updated depends mostly upon the reproduction rate of the carrier. It s quite fast for Drosophila, much slower for Elephantidae. There are different theories, of course, but DNA is not a truly intentional store, at least the way I intend intentional .
Instinctual behavior is DNA-stored active knowledge.
Brain stored knowledge is highly volatile, not only does that knowledge dissipate when its owner dies, it dissipates when its owner doesn t think of the knowledge for a while. The brain is DRAM, not SRAM if the knowledge is not refreshed regularly, it s gone. One of the advantages this brings is that it can be updated quickly. The knowledge in the knowledge store can be replaced and replaced again quite quickly. Even the fundamental structure of the knowledge store can be changed, though with some difficulty.