Uncommon Descent


9 October 2007

Science, E. coli, and the Edge of Evolution: Part 1

Michael J. Behe

Dear Readers,

As I wrote in The Edge of Evolution, Darwinism is a multifaceted theory, and to properly evaluate the theory one has to be very careful not to confuse its different aspects. Unfortunately, stories in the news and on the internet regularly confuse the facets of Darwinism, ignore distinctions made in The Edge of Evolution, or misstate the arguments of intelligent design. The disregard for critical distinctions blurs the issues badly. Over the next few days I will briefly respond to four separate stories
************************
1) A few months ago an interesting paper in Science, “Adaptive mutations in bacteria: high rate and small effects”, by the group of Isabel Gordo demonstrated that beneficial mutations in E. coli were more frequent than had been thought. In fact, the authors remark that “We found a rate on the order of 10(-5) per genome per generation, which is 1000 times as high as previous estimates, and a mean selective advantage of 1%.” They show that the previous underestimates of the beneficial mutation rates were likely due to clonal interference — accumulation of beneficial mutations in large bacterial populations which then interfere with each other to dominate the population, making beneficial mutations seem less frequent. Does this new result mean that Darwinian evolution can construct molecular machinery much easier than thought?
No. While the result is interesting, readers of The Edge of Evolution will not be very surprised by it. As I showed for mutations that help in the human fight against malaria, many beneficial mutations actually are the result of breaking or degrading a gene. Since there are so many ways to break or degrade a gene, those sorts of beneficial mutations can happen relatively quickly. For example, there are hundreds of different mutations that degrade an enzyme abbreviated G6PD, which actually confers some resistance to malaria. Those certainly are beneficial in the circumstances. The big problem for evolution, however, is not to degrade genes (Darwinian random mutations can do that very well!) but to make the coherent, constructive changes needed to build new systems. The bottom line is that the beneficial mutations reported in the new Science paper most likely are degradatory mutations, and so don’t address the challenges outlined in The Edge of Evolution.
Comments are closed.