4 ms·
thinking of DNA as some kind of abstract turing tape is wildly misleading, here's a graphic that summarizes some of the ways DNA is conformed/stored/managed in
by Palomides 7y ago
thinking of DNA as some kind of abstract turing tape is wildly misleading, here's a graphic that summarizes some of the ways DNA is conformed/stored/managed in the cell.
https://upload.wikimedia.org/wikipedia/commons/4/4b/Chromatin_Structures.png https://upload.wikimedia.org/wikipedia/commons/4/4b/Chromati...
each of these have huge implications for what can be done with the DNA
there's tons more information that's attached to the strands of DNA, too, like methylation or promoters, etc. that the simple ATGC doesn't cover at all
if we want to stretch the turing tape metaphor, it's more like marking the symbols as various kinds of magnets on a string, then putting a bunch of them in a sack and shaking them up. does that change the amount of information?
if you're interested, you really can just pick up an intro bio textbook, skim it, then do an intro genetics text (and skip the classical genetics crap).
- mirimir 7y agoOK, so how much could that increase the 800MB estimate? How many orders of magnitude?
- Palomides 7y agolooking at the first step in that graphic, for example, a histone is made of 4 distinct types of parts, and in humans each of those has a dozen variants, and the final assembled histone can additionally be tagged with other pieces. and the physical interaction between the histone and the DNA is influenced by the local sequence. I don't know how I would quantify that, but there's a lot going on.
- deleted 7y ago[deleted]
- jerf 7y agoInformation is a log of the possibilities. Adding epigenetics and such will add to the number of bits, not multiply them. If I give you another decimal digit to stick on to a number, it may give you another factor of 10 to play with on its sum, but it'll still be just one more digit, not a factor of magnitude more digits.
- xg15 7y agoLayman here. I agree, viewing it as a "turing tape" highly misleading - however, I believe the general idea of viewing a cell as a sort of microprocessor with the DNA being the "firmware" is still useful - at least it gave me a better understanding of what kind of information is stored in the DNA at all. Of course, if we stay with that analogy, DNA would not be a "series of instructions" but would more resemble a huge, unordered set of "if/then" rules or "trigger/action" pairs - the "actions" being protein-coding sequences and the "triggers" being their regulatory sequences. The actual behavior of the cell is then determined by the interation of those rules and the effects of the coded proteins.