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by thaumasiotes 745 days ago
> but there is no anatomy coded by genes, no genes code for how many limbs will a biosystem have (as reiterated by Levin)

What's this supposed to mean? We are already able to develop bugs with missing or additional limbs by modifying their genes.
1 comments
spacetimeuser5 745 days ago
At least in a specific experimental context and with specific animal models. When they mixed the embryos of a frog and an axolotl, there were no genes in their genome which could predict whether a "frogolotl" will have legs.
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thaumasiotes 745 days ago
> When they mixed the embryos of a frog and an axolotl, there were no genes in their genome which could predict whether a "frogolotl" will have legs.

You do realize this is untrue?

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spacetimeuser5 744 days ago
That's been reiterated by Levin at almost every presentation. Maybe he's overgeneralizing or there's actually a lack of specific experimental context or reference to a specific study. Maybe "anatomy" is a bit too broad of a term, and the thing inferred is some overall macroscopic patterning, so can't say definitely "untrue", as I haven't yet dedicated time to delve into specific articles and been just consuming lectures/presentations.

But I remember he was mentioning some study in left/right asymmetry in DevBio, where they've shown that it's cell potentials/bioelectric signalling and not genes that determine the left/right asymmetry in embryos.

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thaumasiotes 742 days ago
> where they've shown that it's cell potentials/bioelectric signalling and not genes that determine the left/right asymmetry in embryos.

No, they've shown that electric signaling is how the genes determine the left/right asymmetry in embryos.

How do you think it is that the same thing happens so consistently every time a new organism develops? Where do you think the electric gradients come from?

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