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Michael Levin appears to be demonstrating that cells have a goal-seeking intelligence operating more or less independently of directions from the nucleus. Since

Michael Levin appears to be demonstrating that cells have a goal-seeking intelligence operating more or less independently of directions from the nucleus. Since literally every cell on earth arose by fission from another cell, the lineage of this intelligence goes back in an unbroken line to their first common ancestor billions of years ago, with natural selection operating on it directly by success at solving problems of survival and reproduction in real time, not just via selection of genes. In a similar way, every membrane in every cell came from extending and then splitting an existing membrane, again more or less independently of the nucleus. Natural selection has operated directly on those membranes, besides its role in adapting the genes that code for subunits of the membranes. The nucleus might be thought of as mainly a library of apparatus that the cell's goal-seeking capacity may draw upon as needed. This analogy is necessarily limited because there are innumerable feedback control cycles encoded in genes and repressor and promoter proteins they encode, and enzymes to methlylate or de-methylate start and stop codons. But something is in charge that operates on a shorter scale than those can. We understand very, very little about that intelligence. It is far more capable than we could ever have guessed. It barely seems possible, with as few moving parts as we know about.

ace2358 3y ago
Lovely insight
crotchfire 3y ago
the lineage of this intelligence goes back in an unbroken line to their first common ancestor billions of years ago, Nonsense. If cell walls ever had the ability to replicate themselves, totally autonomously, without the rest of the cell -- they've very certainly lost that ability. That loss of self-sufficient replication is quite a big "break" in the line. Your argument might apply to ribosomes, however. The nucleus needs the ribosome for replication every bit as much as the ribosome needs the nucleus. And the ribosomal DNA is one of the very, very rare things that has hardly changed at all in the history of life -- humans and yeast have 75%-identical ribosomal DNA. Yeast! https://en.wikipedia.org/wiki/Ribosomal_DNA https://en.wikipedia.org/wiki/Ribosomal_DNA
- angiosperm 3y ago
  I think you miss the point. Every scrap of membrane in every cell in every known organism -- and cells have a lot of different membranes in them -- was once part of a membrane in the parent cell, or was one of several in a parent cell that became part of this or that daughter cell. We don't know of any organism that constructs any membrane for any purpose de novo. In a very real sense, life may be defined as a membrane with apparatus to aid in growing it. So, in that sense, every evolutionary change is ultimately a refinement to enable growing more membrane. You, personally, are a lot of membranes all folded and wrapped up and carrying around a skeleton.
zmgsabst 3y ago
> In a similar way, every membrane in every cell came from extending and then splitting an existing membrane, again more or less independently of the nucleus. Can you elaborate? As I understand it, the manufacturing of the cell membrane and coordination of splitting with other features (eg, intracellular features that pull it apart) requires the DNA transcription and is regulated by particular genes. That is, depends on the nucleus.
- angiosperm 3y ago
  Proteins are certainly involved wherever membranes are grown, and proteins are coded for in the nucleus. But the membranes are always there first. No cell anywhere in nature, as far as we know, just makes any membrane from one lipid and then another; membranes are only made by extending an existing membrane.
  - zmgsabst 3y ago
    The hypothesis is that coding molecules predate cell membranes. So we have “every current cell membrane requires the nucleus” and “the coding portion came first”; nobody is disputing that membranes build on membranes, just pointing out they integrally depend on the nucleus to operate (coding for proteins) — and always have. > again more or less independently of the nucleus Ie, this is wrong.
    - angiosperm 3y ago
      There was a time when there was no nucleus, and no DNA. But there were membranes and RNA.
dekhn 3y ago
everything about cell membranes splitting would need to be encoded in the germ plasm of the embryo (because all cells derive from that one). Can you point to the information-encoding information in the germ plasm which is not in the nucleus? Everything we know about cell biology currently suggests that everything required for cell membranes is implemented by proteins controlled by regulated expression of DNA. For natural selection to operate directly on membranes would be a fantastic discovery but would require some pretty challenging experiments to demonstrate convincingly.

ace2358 3y ago

Lovely insight

crotchfire 3y ago

the lineage of this intelligence goes back in an unbroken line to their first common ancestor billions of years ago, Nonsense. If cell walls ever had the ability to replicate themselves, totally autonomously, without the rest of the cell -- they've very certainly lost that ability. That loss of self-sufficient replication is quite a big "break" in the line. Your argument might apply to ribosomes, however. The nucleus needs the ribosome for replication every bit as much as the ribosome needs the nucleus. And the ribosomal DNA is one of the very, very rare things that has hardly changed at all in the history of life -- humans and yeast have 75%-identical ribosomal DNA. Yeast! https://en.wikipedia.org/wiki/Ribosomal_DNA https://en.wikipedia.org/wiki/Ribosomal_DNA

angiosperm 3y ago
I think you miss the point. Every scrap of membrane in every cell in every known organism -- and cells have a lot of different membranes in them -- was once part of a membrane in the parent cell, or was one of several in a parent cell that became part of this or that daughter cell. We don't know of any organism that constructs any membrane for any purpose de novo. In a very real sense, life may be defined as a membrane with apparatus to aid in growing it. So, in that sense, every evolutionary change is ultimately a refinement to enable growing more membrane. You, personally, are a lot of membranes all folded and wrapped up and carrying around a skeleton.

zmgsabst 3y ago

> In a similar way, every membrane in every cell came from extending and then splitting an existing membrane, again more or less independently of the nucleus. Can you elaborate? As I understand it, the manufacturing of the cell membrane and coordination of splitting with other features (eg, intracellular features that pull it apart) requires the DNA transcription and is regulated by particular genes. That is, depends on the nucleus.

angiosperm 3y ago
Proteins are certainly involved wherever membranes are grown, and proteins are coded for in the nucleus. But the membranes are always there first. No cell anywhere in nature, as far as we know, just makes any membrane from one lipid and then another; membranes are only made by extending an existing membrane.
- zmgsabst 3y ago
  The hypothesis is that coding molecules predate cell membranes. So we have “every current cell membrane requires the nucleus” and “the coding portion came first”; nobody is disputing that membranes build on membranes, just pointing out they integrally depend on the nucleus to operate (coding for proteins) — and always have. > again more or less independently of the nucleus Ie, this is wrong.
  - angiosperm 3y ago
    There was a time when there was no nucleus, and no DNA. But there were membranes and RNA.

dekhn 3y ago

everything about cell membranes splitting would need to be encoded in the germ plasm of the embryo (because all cells derive from that one). Can you point to the information-encoding information in the germ plasm which is not in the nucleus? Everything we know about cell biology currently suggests that everything required for cell membranes is implemented by proteins controlled by regulated expression of DNA. For natural selection to operate directly on membranes would be a fantastic discovery but would require some pretty challenging experiments to demonstrate convincingly.