Re: We believe in design

I'll probably bow out now as your knowledge of biology is far superior to
mine, so there's not much point arguing from ignorance ...

However one comment:

>
> On the contrary, fitness surfaces are strongly
> affected by neutrality.

Look at for instance RNA and the work done in this
> area. Combine this with the scale free nature of RNA,
> realize that a simple process of duplication and
> preferential attachment can explain scale free
> networks and one comes to understand why RNA sequence
> space extends through and that the common RNA
> structures are close to any other common structure
> within space, connected by neutral pathways which
> extend throughout space.

I'll just say that this was not how I understood the two examples in the
Toussaint paper. I agreed with you that duplication could indeed change the
fitness surface because it actually alters the dimension of sequence space:
what is a local minimum in N dimensional space may become a saddle-point in
(N+n)-dimensional space.

But the two examples in the Toussaint paper were not like this. In one case
the neutrality (by having for example nine different codons for one amino
acid) affected the effective mutation rate at different points in the
genome. In the artificial case, an extra segment of the genome was not
affecting the phenotype but did code for the mutation rate. In neither case
does this do anything more than produce an accelerated learning algorithm,
just like my neural-network-with-adaptive-learning-rates example. Neither
example (as I recall from my brief reading of the paper) altered the size of
the genome.

As I said in the earlier post, gene duplication looks a more promising
avenue if you're talking about design (or adaptation) of the fitness
surface.

I guess anyone on this list who is a Christian ultimately believes God
designed it all - intended the universe to be so that intelligent creatures
appeared who would be aware of their creator. Most people on this list would
call themselves "Theistic Evolutionists", implying that God chose to create
via the process of evolution. I would count myself in that camp these days.

I'm wondering where you stand on this, Pim? You haven't said.

Iain
Received on Sat May 28 16:46:42 2005