Is the intelligent design lobby good for something after all?
In a recent article (subscription required) in the New Scientist (2008-02-16), Dan Jones reports on the state of the investigations into the possible origins of the flagellum, a propeller-like organ in the wall of a bacterium that can be used to move it through the water. This particular feature of cells has become a reluctant bell-wether in the debate about evolution, because it is often brought up as something that must have been designed. Well, progress is being made in elucidating the relationships between the proteins used in the flagellum, and other proteins used for various jobs around the cell.
The flagellum consists of three parts, which in engineering terms can be thought of as the rotor of a turbine, attached to the shaft of which is a hook, onto which in turn is a blade. The rotor is embedded in the cell wall and the hook ensures that the blade swings in a wide arc. How did these three items combine in just this manner?
Well it appears that the proteins used to build it are coded for by genes very similar to many other genes, so it is not surprising that easy mutations can create the building blocks for the whole mechanism. It was cobbled together from parts left around in the yard. But, further, it is very similar indeed to a tunnel and prong used by some bacteria (e.g. Salmonella) to inject other cells. An almost identical mechanism is used to load the prong with a toxin as is used by the flagellum to repair damage to the blade.
What is uncertain at the moment is the order of development, and scientists, being scientists, are engaged in their usual debates in the academic journals for all to read and follow. This is as it should be; we are still far from being able to identify all the relations between the parts, and after more than 3 billion years of unwritten and lost history we may never know enough to give a definitive answer. But the more we know, the more likely it is a consensus will emerge.
The intelligent design advocates have done one good thing for science, but not in the way they had hoped. They have caused biologists to concentrate on a target to find the counter-arguments, discover new methods of analysis, and investigate how genes and proteins change over time. As Dan Jones says, it's now time for the other side to say what progress they have made in refining their ideas on their reasons to support a design-based “theory”.