Evolvable by design

By PvM

The work by Panos Oikonomou, a graduate student at the Physics Department, University of Chicago, recently caught my eye. His website explains that he is

… interested in studying the relationship between network topology, dynamics and evolution. I explore possible evolutionary advantages of such features, like the scale-free distribution.

He recently wrote a paper “Effects of topology on network evolution”, Panos Oikonomou and Philippe Cluzel, Nature Physics, August 2006.

In the paper, the authors compare the characteristics of a random network versus a scale free network. A random network is one in which each node has on the average the same number of connections to other nodes. For scale free networks, the connectivity follows a power law distribution. They tested how the two different networks ‘responded’ to evolutionary processes

Our simulations show that populations containing these scale-free networks can easily produce a number of functional variations which allow each population to evolve rapidly and smoothly towards some target function. By contrast, equivalent random networks evolve slowly, through a succession of rare fortuitous random mutations.

The work is particularly relevant because 1) scale free networks can be found at all levels in nature 2) scale free networks can be explained by processes as simple as gene duplication and preferential attachment.

What is even more interesting is that

For systems randomly connected it is necessary to invoke a specific tuning of their connectivity in order to access the target faster, however such fine-tuning is not required for scale-free networks.

In other words, scale free networks seem to have many features which make them very suitable for evolutionary processes. So next time you hear ID proponents argue that the networks of interactions of genes inhibits evolution, you may ask them about scale free networks. In addition, one may ask them how ID explains these findings?

“The problem of biology is not to stand aghast at the complexity but to conquer it”, Sydney Brenner, Discover Dialogue, April 2004

As to the origin of complexity? These findings are but one piece of the puzzle being slowly unraveled by science.

What has ID done for science lately?