interesting idea. how cool would that be if it were true! i did a quick google on brain and DNA capacity and found a reference that indicated that the brain contains around 100 GB of data and the human genome contains about .35 GB (forget the stuff about data capacity of the enitre body, since most is redundant). another known estimate is that humans can process about 2 bits per second of data. based on that, here are a couple thoughts...

- since a visual image collected on the visual cortex may be in the 100 MB range, and we see hundreds of such images per minute, it is clear that we do not retain all of that information in the brain.

- it is also clear that there isn't enough memory capacity in DNA to store much more than a few minutes of visual experiences.

- despite these calculations, it appears that there are people who retain vivid recollections of the past (so called photographic memory) or other feats of memory that can't be explained by traditional models

so, if DNA is structured as we think it is, it really can't hold much information. there isn't any evidence either that actual sensory experiences are stored there.

however, there is a school of thought that collective human (or other) experiences are stored in the "ether", "akashic record", "zero point field" - whatever you want to call it. the holographic paradigm suggests that all that has happened past and present is available "out there." no hard evidence for it yet, but it certainly can't be ruled out.

and, of course, since i always end posts like this with the old "what does programmed reality say about this", i have to say that if reality is programmed, the engine that drives it is way beyond anything we have "real experience" with and would therefore certainly have the capacity for such storage. so, programmed reality explains the "Rain Man" effect and any other memory feat you can find.