Thursday, September 11, 2008

A decentered biology

So we talk and I have to update image after image and image to keep up. Whatever ideas I have about the mechanics of the passing of secret messages break under the weight of your epigenetics.

DNA is still the repository; check. RNA still transient? Um, kinda. But these 'maternal effect' factors? This stuff that hangs out in the cortex ... who the hell cares about the cortex? I couldn't ante up a damn thing about the cortex. The nucleus is where all the information lives, right? And information equals control, and control is what manages change, and development is change, and so the nucleus is center stage for development ...

Or maybe not.

The cell divides and somewhere by 8 or 16 or something daughter cells differentiation sets in. Something is inside, something is outside. And nowhere in any of the stuff they shoved down our throats in school was there any clue of a reason as to why differentiation actually happened: the daughter cells all have the same DNA, right?

But what if precisely that stuff that's hanging out in the cortex can actually play a role? What if the stuff that's hanging out in the cortex isn't distributed evenly around a too-smooth sphere but actually has a COMPLEX PATTERN -- or maybe better a complex SERIES OF PATTERNS -- to its distribution. And what if the patterning inherent in the distribution of the magic stuff of the cortex matters precisely because the different daughter cells grab different parts of the cortical information as they cleave?

More head blowing up. Because what happens is that the intolerably round, intolerably centered model of the perfect egg dissolves: we can't answer the question of fundamental differentiation when there's too much symmetry, that is, when we think according to too perfect a model. The tyranny of the sphere. What's needed is precisely asymmetry in an amount enough to decenter the model. Enter the edge of the cell as the source and keep of just the asymmetry we need. And we start to explain why we get a head over here but a tail over there.

If this is right -- if magic stuff living in the remote edges of the cell acts as type of control over the all-important information in the central repository that is DNA -- then what we have is a decentered biology. A molecular biology that yields up the secrets of its center in its first 60 years and opens its edges only now.

RNA as the winged messenger. How else to explain how the stuff at the edges -- in the form of these maternal effect factors -- can actually effect control? Stuff, in the form of (m)RNA has to visit the factors present in the cortex. And so a new image: a visit there and back again as critical to development. This is the image of the pilgrimage.

Put it together and the centered repository part of the model sticks around. But the model augments centralization with control from the periphery. All by means of developmental pilgrimage upon developmental pilgrimage.

As you get closer and closer to the image of the epigenome I see colors. Literally. A dusting of green and sapphire specks, scattered rainbow colors in the shadows of the cell, patterned to control, to help, to develop, to break a tyranny of too much symmetry.