Science a GoGo's Home Page Forums General Discussion Not-Quite-Science Forum Reply to Paul re Neat Experiment

the machinery for both transporting and metabolizing citrate was already present in these bacteria. But a series of knockout mutations broke the regulation of pre-existing citrate transport mechanisms, causing over-expression of a citrate transport gene, allowing citrate to be transported under both oxic and anaerobic conditions. If this is the case, then clearly this example of Darwinian "evolution" entails the loss of a molecular function, not the gain of a new one. And there was no wholesale acquisition of the ability to metabolize or, as Venema put it, "use" citrate.
In fact, as Behe notes, we don't really yet understand the precise molecular mechanisms that caused these E. coli to be able to uptake citrate under oxic conditions. So as far as we can tell, these changes entailed the origin of no new functional genes or proteins but might have resulted from a broken regulatory mechanism. We have not seen that natural selection and random mutation can produce functional, information-rich genes and proteins, and Venema is wrong to suggest otherwise.

Contra Venema, this example hardly shows the Darwinian evolution of a "new function," especially since E. coli already had the ability to uptake and metabolize citrate. Venema claims that CSI has arisen, but if we don't even know what mechanisms were involved in this change, how does he know that it is new CSI?