Here's Complexity in your eye...fruit fly

Nature, v. 431, 7 Oct. 2004, p. 635, "Holding it together in the eye, by Paul A. Janmey and Dennis E. Discher references "Surface mechanics mediate pattern formation in the developing retina" by Hayashi and Carthew, pp. 647-652.

There seems to be a bit of excitement here over our advancement in understanding the complex process of forming multicellular organisms. And it can be very complex: "In a developing tissue or organism containing dozens or even thousands of different cell types, the formation of uniquely structured subsets of cells is a complex process. It can involve cell motility, cell adhesion, attractive and repulsive signalling, and other factors, all of which are controlled by their own network of biochemical reactions."

The report in this issue merely deals with the formation of the fruit fly eye, "an attractive model for studying development, because it is a relatively small and simple organ, formed by a limited number of cell types." Actually, the researchers focused on just part of this "simple" organ -- to be specific, the pattern formed by clusters of four cells of the same type! They show that it is very similar to the pattern made by four soap bubbles, and demonstrate that a protein that makes cells stick together is responsible. Of course, these cells don't actually clump together as simply as soap bubbles.

"The proteins...and phospholipids that hold one cell membrane to another...are very different from the simple surfaces that partition a collection of bubbles" and "cells are filled not with fluid but with a viscoeleastic protein skeleton, both within the cell interior and lining the cell surface."

So, while "the lows of physics, which underlie all biological processes, are not always obscured by the dazzling molecular complexity of biology," the tiny scratches we have made in attempting to mine the mountain of examples of this complexity continue to indicate that the origin of such complexity cannot be explained by those laws.

Until Next Time,

David Bump
Philippians 3: 13 Brethren, I
count not myself to have
apprehended: but [this] one thing
[I do], forgetting those things
which are behind, and reaching
forth unto those things which are
before, 14 I press toward the
mark for the prize of the high
calling of God in Christ Jesus.

http://home.att.net/~david.bump