Verdict on the Bacterial Flagellum Premature:
A Response to Begley's "Evolution Critics Come Under Fire..." in the Wall Street Journal
February 19, 2004
Your February 13th Science Journal reports on the fascinating debate between biochemist Michael Behe and biologist Ken Miller (“Evolution Critics Come Under Fire for Flaws In ‘Intelligent Design’”) about the origin of the miniature machines in living cells. Your article summarizes Behe's “irreducible complexity” argument and Miller’s counter argument, but does not report on Professor Behe’s response or other scientific critiques of Miller's “co-option” scenario. Consequently, it's verdict in favor of Professor Miller is premature at best.
It's true that the tiny cellular pump that forms part of the flagellar mechanism can also function separately in other contexts. Superficially, this does seem to support Professor’s Miller’s contention that “natural selection” could have “co-opted” functional parts from earlier simpler systems to produce the flagellar motor, especially since the pump is made of ten proteins that are also found in the forty-protein motor that Professor Behe has made so famous. Case closed?
Not quite. Milleršs scenario faces at least key three difficulties. First, the other thirty or so proteins in the flagellar motor are unique to it and are not found in any other living system. From where,then, were these protein parts co-opted? Second, as flagellum expert Prof. Scott Minnich points out, even if all the protein parts were somehow available to make a flagellar motor during the evolution of life, the parts would need to be assembled in a specific temporal sequence similar to the way an automobile is assembled in factory. Yet, in order to choreograph the assembly of the flagellar motor, present-day bacteria need an elaborate system of genetic instructions as well as many other protein machines to regulate the timing of the expression of these assembly instructions. Arguably, this system is itself irreducibly complex. In any case, the co-option argument tacitly presupposes the need for the very thing it seeks to explain‹a functionally interdependent system of proteins. Third, analyses of the gene sequences of the two systems suggest that the flagellar motor arose first and the pump came later. In other words, if anything, the pump evolved from the motor, not the motor from the pump.
Stephen C. Meyer, Ph.D.
Director and Senior Fellow
Center for Science and Culture
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