[gilleain]

I think this is 'Reaction-diffusion models'

https://en.wikipedia.org/wiki/Reaction%E2%80%93diffusion_sys...

The idea iiuc, is that pattern formation in animals depends on molecules diffusing through the growing system (the body) and reacting where the waves of molecules overlap.

[Kim_Bruning]

To me , the 1952 paper is very important, since it shows up in theoretical biology a lot. Seeing generality at all these different emergence levels is really exciting to me. (and it makes me sad when others don't see it). Can you imagine? Set up a few gradients, and now you have coordinates. Put all the bits where they're supposed to go like uhhh... GLSL sort of loosly fits. How cool is THAT?

More recently I've gotten into all sorts of debates on HN by people who like Searle. Often the argument goes "Turing is all wrong, he knows nothing about biology."

Turns out towards the end of his life he was applying his knowledge to biology. Most of which experimentally verified, besides!

(ps. just to be sure: Never wondered how DNA encodes the trick? You started out as a clump of cells, all the same. How did one part decide to become the tip of your nose, and the other the tips of your toes? Segmentation controlled by Turing patterns all the way down!)

[amiga386]

> How did one part decide to become the tip of your nose, and the other the tips of your toes?

Homeobox genes, right?

https://en.wikipedia.org/wiki/Morphogenesis

Yes, https://en.wikipedia.org/wiki/The_Chemical_Basis_of_Morphoge...

But also:

https://en.wikipedia.org/wiki/Body_plan#Genetic_basis

https://en.wikipedia.org/wiki/Homeobox

https://en.wikipedia.org/wiki/Hox_gene

https://en.wikipedia.org/wiki/Gene_regulatory_network

https://en.wikipedia.org/wiki/Epigenetics

https://en.wikipedia.org/wiki/Cell_potency

https://en.wikipedia.org/wiki/Evo-devo

https://www.youtube.com/watch?v=ydqReeTV_vk