Re: Directed evolution: evidence for teleology?

Glenn,

> > 1. Are there any distinctive watermarks left behind in the
> > process(es) of directed evolution that could potentially
> > allow one to discern an enzyme so optimized from one that was
> > already "designed" by evolutionary processes over time?
>
> In princiiple, yes, there could be a watermark which would distinguish
> special creation from evolution. Contra Ms. Freeman. But I would agree with
> her that it is a waste of time to attempt to find it. Here is what I would
> take to be evidence of special creation vs. evolution---if one could prove
> that the enzymes in the body were GLOBALLY the most efficient enzymes
> possible. Evolution would be expected to find the most efficent enzyme on a
> local level of the sequence space.
> But because of computational limitations, it is an utter waste of time to
> attempt this program.

Agreed, if we had to search the entire protein. But it has been shown
many times that substituting any individual amino acid, say, on a 250
residue protein (roughly the size of cytochrome c oxidase) that the
enzyme would probably still work, since its activity depends
principally upon only a 20 residue section and directly on as few as
three residues. Indeed, I've seen papers where a single residue was
shown to be necessary and sufficient for an enzyme's activity, in the
environment of the others. So the task might still be doable for
individual enzymes that have this property.

Vern Schramm and his research group has done quite a bit of work in
finding substrates for enzymes that are as good as their known
substrates, for the purpose of drug discovery. The potency of these
molecules is many times more than is usually discovered (or even
desired) for drug potency, which suggests that enzymes are quite
optimal indeed. However, if one could produce a cytochrome c oxidase
by directed evolution that performed its role better, then it could be
treated as evidence against God's action. But it could just as easily
be treated as God wisely making the site suboptimal so as to preserve
an ancillary function of the enzyme in hostile environments (what do
we mean by role anyway?). It could even be treated eschatologically,
i.e. God doesn't want cyt c to perform optimally yet for reasons that
are His own. I look at this problem as the main reason why "inferring
design" probably can't be formulated in a scientific manner.

Chris
Received on Sat Oct 15 12:22:38 2005