11.11.08

Evolutionary control systems

Posted in Evolution at 6:53 pm by nemo

Evolution’s new wrinkle: Proteins with cruise control provide new perspective
by Kitta MacPherson · Posted November 10, 2008; 10:00 a.m.
So long Darwin.
This article was cited yesterday without comment, but deserves a thorough look.
Here’s a short quote. Note, once again, the rightness of Wallace’s instincts.
As a critic of natural selection, I never asked for anything more as a substitute than something that could ‘increase the odds’ toward the emergence of any given evolutionary change.
What better than simple feedback in a control system?
Perhaps now the basic issue of the eonic effect/model will seem thinkable. we see a ‘control system’ (although I move past such terms) operating over the long range of evolutionary emergence.

A team of Princeton University scientists has discovered that chains of proteins found in most living organisms act like adaptive machines, possessing the ability to control their own evolution.

The research, which appears to offer evidence of a hidden mechanism guiding the way biological organisms respond to the forces of natural selection, provides a new perspective on evolution, the scientists said.

The researchers — Raj Chakrabarti, Herschel Rabitz, Stacey Springs and George McLendon — made the discovery while carrying out experiments on proteins constituting the electron transport chain (ETC), a biochemical network essential for metabolism. A mathematical analysis of the experiments showed that the proteins themselves acted to correct any imbalance imposed on them through artificial mutations and restored the chain to working order.

“The discovery answers an age-old question that has puzzled biologists since the time of Darwin: How can organisms be so exquisitely complex, if evolution is completely random, operating like a ‘blind watchmaker’?” said Chakrabarti, an associate research scholar in the Department of Chemistry at Princeton. “Our new theory extends Darwin’s model, demonstrating how organisms can subtly direct aspects of their own evolution to create order out of randomness.”

The work also confirms an idea first floated in an 1858 essay by Alfred Wallace, who along with Charles Darwin co-discovered the theory of evolution. Wallace had suspected that certain systems undergoing natural selection can adjust their evolutionary course in a manner “exactly like that of the centrifugal governor of the steam engine, which checks and corrects any irregularities almost before they become evident.” In Wallace’s time, the steam engine operating with a centrifugal governor was one of the only examples of what is now referred to as feedback control. Examples abound, however, in modern technology, including cruise control in autos and thermostats in homes and offices.

The research, published in a recent edition of Physical Review Letters, provides corroborating data, Rabitz said, for Wallace’s idea. “What we have found is that certain kinds of biological structures exist that are able to steer the process of evolution toward improved fitness,” said Rabitz, the Charles Phelps Smyth ’16 Professor of Chemistry. “The data just jumps off the page and implies we all have this wonderful piece of machinery inside that’s responding optimally to evolutionary pressure.”

The authors sought to identify the underlying cause for this self-correcting behavior in the observed protein chains. Standard evolutionary theory offered no clues. Applying the concepts of control theory, a body of knowledge that deals with the behavior of dynamical systems, the researchers concluded that this self-correcting behavior could only be possible if, during the early stages of evolution, the proteins had developed a self-regulating mechanism, analogous to a car’s cruise control or a home’s thermostat, allowing them to fine-tune and control their subsequent evolution. The scientists are working on formulating a new general theory based on this finding they are calling “evolutionary control.”

Permalink