Over at Biologic Institute, Ann Gauger responds to Paul McBride (a commenter here),
The reason for our choice was not ignorance. We knew that the enzymes we tested were modern, and that one was not the ancestor of the other. (They are, however, among the most structurally similar members of their family, and share many aspects of their reaction mechanism, but their chemistry itself is different.) We also knew that in order for a Darwinian process to generate the mechanistically and chemically diverse families of enzymes that are present in modern organisms, something like the functional conversion of one of these enzyme to the other must be possible. We reasoned that if these two enzymes could not be reconfigured through a gradual process of mutation and selection, then the Darwinian explanation of gene duplication and gradual divergence to new functions was called into question.
Our results indicated that a minimum of seven mutations would be required to convert or reconfigure one enzyme toward the other’s function. No one disputes that part of our research. What Paul McBride and others claim is that because we didn’t start from an “ancestral” enzyme, our results meant nothing. They say something like, “Of course transitions to new chemistries between modern enzymes are difficult. What you should have done is to reconstruct the ancestral form and use it as a starting point .”
Have you noticed the assumption underlying this critique? The assumption is that genuine conversions can be achieved only if you start from just the right ancestral protein. Why is that? Because conversions are hard.
McBride said as much in his post, tacitly acknowledging the legitimacy of our results, in the following quote: … More.
Ann, Darwinists dispute whatever they need to, like used car salesmen defending a lemon you bought. Don’t even discuss it with them if you don’t have a big, stupid guy with you or, much better, a lawyer.