Yesterday at Pharyngula, PZ posted a description of his favorite signaling pathway in developmental biology, the [Notch system.][notch] Notch is
a cellular system for selecting one cell from a collection of essentially indistinguishable cells, so that that one cell can take on some different role.
What I found striking was that the problem that Notch solves is extremely similar to one of the classic problems of distributed systems that we study in computer science, called the leader-election problem; and that
the mechanism used by Notch is remarkably similar to one of the classic
leader-election algorithms, called the [Itai-Rodeh algorithm][ir].
[notch]: http://scienceblogs.com/pharyngula/2006/12/notch.php
[ir]: http://citeseer.ist.psu.edu/itai81symmetry.html
Before I go into detail, I think it’s worth throwing a bit of a dig at
some of the IDist type bozos. This is very much the kind of thing
that IDists look for; they try to find natural systems that strongly
resemble designed systems, so that they can assert that the natural
system must have been designed. But the people allegedly doing ID
research *don’t bother to study the fundamental science*. No one in
ID-land is studying developmental biology, to really understand
the complex signaling pathways, and what I would call the algorithmic
way that they operate. I think it’s quite damning to their arguments
that they don’t study this; but I also think I know *why*. If you
read PZs article, and you starting looking in depth into developmental
pathways, and understanding how they fit together, and how very small
changes in a process can produce drastically different results – well, it
really sort of pulls the carpet out from under the ID argument. You can really see just how these systems evolved in terms of gradual changes. Just look at Notch – how simple the behavior is, how widely it’s used to produce very *different* kinds of differentiation, and how easily the
process can be perturbed to produce different results.

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