Comment by breatheoften | Hacker News Reader

Comment by breatheoften | Hacker News Reader

There was a really interesting episode of the mindscape podcast[0] recently which discusses a system in Planaria where the expression of the way the worm grows (with one head or two) is found to be encoded in an electronic structure within the tissue of the worm -- rather than within the worm's DNA.

In a very real and observable sense, the 'blueprint' for the target worm is stored in the tissue system rather than as a 'plan' stored in the DNA itself. I think it feels surprising to see something that seems a lot like 'memory' influencing the action that results in the expression of the complete organism via the cellular level processes in this way.

I find it easy to postulate from the example of planaria that analogous 'memory encoding' systems probably exist in all sorts of cellular systems ... though I think the information theoretic reasoning referenced by the participants in that podcast for how life creates and operates these systems makes it likely that 'the existence of information storage and retrieval' in a cellular system is not at all required to imply that 'this kind of system is therefore the storage model for long term cognition'.

[0] https://www.preposterousuniverse.com/podcast/2021/02/01/132-...

I had surgery which left me with scar tissue; years later another surgery removed it, and I carefully padded and taped over it, hoping it would settle at skin level. It pushed on, I got nurses to apply chemical cauterization, it still filled out until it was back the same as before, then stopped. Maybe 1 cubic cm of flesh. That's not in my DNA, I wasn't born with that, why did it grow and why did it regrow both times differently to how I grew from conception?

See also this talk by Prof. Michael Levin, same guy as your podcast - https://news.ycombinator.com/item?id=18736698 - titled "What Bodies Think About: Bioelectric Computation Outside the Nervous System", including from the top comment by keithwhor:

" - Organism morphology seem to be highly dependent upon large-scale electrical potential differentials between cells

- These electrical networks are primarily regulated by cell-to-cell gated ion channels; simple chemical pumps (the same types of membrane proteins that control faster-acting electric potentials that enable muscle contraction, neural activity)

- These networks and patterns of bioelectric signalling have stable memory (once a pattern between cells is induced, it remains stable) and are responsible for driving "subroutines" of large groups of cells -- morphological gene, protein expression downstream of this "

Michael Levin's work seems incredibly important and one of the most likely truly breakthrough discoveries I've heard of in a long while. I'm not so sure about RNA memory storage but the point about unicellular life possessing some form of information processing ability is certainly something more people should be thinking about. The fact that such complex behaviour is possible on that minuscule of a scale means there is really something special about the computational properties of organic chemistry. I can't help but feel a lot of the hardware that makes up macro scale life is really just used for dealing with the inefficiencies of getting so many individual cells to cooperate and interface with their environment in a coordinated manner. Single celled organisms have a shorter round trip time for their decision - action - sensation loop but are generally unable to make major modifications to their surroundings by acting or moving. Nonetheless, I think they're a lot smarter than we give them credit for.

> "The fact that such complex behaviour is possible on that minuscule of a scale"

It's a small scale, but it's not empty; ask yourself how many atoms are in a human cell, then check this link for an answer and see how close you are: https://www.thoughtco.com/how-many-atoms-in-human-cell-60388...

Wow! That is such a surprising fact. I’m not going to post my guess because that would influence this for others, but... do guess and click that link.

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