Posted: Dec 23, 2010 1:00 pm
Shrunk wrote:
It seems to me there is a more basic conceptual problem with Behe's idea: His distinction between "gain of function" and "modification of function". While that might make some sense generally, in terms of promoting ID over evolution (assuming that is his true motivation in writing this paper) I think he oversells this idea.
I'm less sure - as defined below, I think this is a very honest and fair way of interpreting a modification of function.
"Another population indigenous to some
malarial regions has a different point mutation
in their hemoglobin. In this instance,
the sixth codon of the chain has
mutated from glutamic acid to lysine. Although
the altered hemoglobin (HbC)
does not aggregate as sickle hemoglobin
does, it confers resistance to malaria for
reasons that are unclear. Because apparently
no new, discrete, coded molecular
feature has been developed, this is categorized
as a “modification-of-function” adaptive
mutation; no FCT has been lost or
gained."
As to the inferences then drawn - that is a different matter. One can certainly propose that functionally equivalent alleles can still create differences over time and it would appear that there is good evidence for that. However, modifications that change a fin to an arm would certainly not fit this mould, that would definitely require some change in function. To assert that equivalent alleles lead to such changes requires evidence somewhere along the line for a gain or loss of function.