In a 2009 post from the Discovery Institute’s “Evolution News” blog, Michael Behe writes the following when discussing a study published by Joe Thornton’s lab:
Now back to Thornton’s first point, the role of neutral mutations (which he sometimes labels “permissive” mutations). At several places in his post Thornton implies I’m unaware of the possibilities opened up by genetic drift:
Behe’s discussion of our 2009 paper in Nature is a gross misreading because it ignores the importance of neutral pathways in protein evolution…. Behe’s first error is to ignore the fact that adaptive combinations of mutations can and do evolve by pathways involving neutral intermediates…. As Fig. 4 in our paper shows, there are several pathways back to the ancestral sequence that pass only through steps that are neutral or beneficial with respect to the protein’s functions.
My interest in evolution by neutral mutation, however, is a matter of public record. It is an old idea that if a gene for a protein duplicates (3), then multiple mutations can accumulate in a neutral fashion in the “spare” gene copy, even if those mutations would be severely deleterious if they occurred in a single-copy gene.
Anyone with a reasonable understanding of current evolutionary theory will recognize that what Behe describes there is not what is referred to as “evolution by neutral mutation.” A correct description of this idea is given in the following article:
Neutral Theory: The Null Hypothesis of Molecular Evolution | Learn Science at Scitable
It is also apparent to me that pretty well every single one of Behe’s major arguments against evolution is based on this failure to appreciate this single aspect of the current theory of evolution. Specifically, he repeatedly asserts that biological features requiring several mutations can only arise if each individual mutation is subject to positive selection. In one publication, in fact, he uses a model in which all mutations other than the ones in question are subject to negative selection.
As I see it, if Behe were to understand and acknowledge neutral theory he would also have to retract almost every word he has written on evolution in his career as a proponent of Intelligent Design.
Am I wrong in this assessement? If so, can anyone quote where Behe demonstrates a correct understanding of all aspects of modern evolutionary theory, and neutral theory in particular?