"Tim Tyler"  wrote in message
news:c7rcpq$kqm$1{at}darwin.ediacara.org...
> Jim Menegay  wrote or quoted:
> > Tim Tyler  wrote in message
news:...
>
> > > [Autocatalysis]
> > >
> > > This seems to be Eigen's idea - much as re-described by Kauffman.
>
> [...]
>
> > > My impression of the autocatalytic story is that it fails
> > > to present a convincing story to account for heredity.
> > >
> > > The story it *does* produce to account for heredity is based more
> > > on computer modelling than it is on chemistry.  I can't see any
> > > good reason to think it would ever actually work. [...]
> >
> > I myself tend to believe the autocatalysis story, though I can't
> > offer any facts to counter Tim's skepticism.  Most accounts of
> > autocatalysis - particularly Kauffman's - are not very convincing.
> > Here is one that is better than most, though it too relies on
> > computer modeling.  The idea that makes it a little better than
> > most such efforts is that it relies on two-dimensional self-organized
> > structures (i.e. membranes) as the carriers of the chemical activity.
> > This means that the catalysts don't need to be quite as powerful,
> > though they still need to be fairly specific.
> >
> > http://emboreports.npgjournals.com/cgi/reprint/1/3/217
>
> It's a well-presented paper.
>
> ``But how could such lipid assemblies carry and propagate information?''
>
> ...is followed by a bit of a fudge paragraph, though.
>
> I'm sure Jim could give a much more coherent answer ;-)

Everyone fudges - because no one has the complete OOL theory
yet.  My intuitions are different from those of the paper in
several ways - most notably in that I want to put my organisms
of a soup-free diet as soon as possible.  Any organics that they
consume should be home-cooked.  None of those nasty tars
that Miller makes.  Autrotrophy is essential.  IMO.

But one thing that should be recognized by people who claim
that autocatalytic cycles can't provide enough heritable
variation:  When "mutation" happens and a new cycle is
ignited and becomes part of the genome, this does not
correspond to adding a new base pair.  It doesn't even
correspond to adding a new functional gene.  It is more
similar to adding a whole new multi-gene operon to the
genome - a whole new chapter of the biochem textbook.
Mutations always work, in the computer programmer's
sense - they do something coherent, but it may not be
what the user wanted.

So, the evolution of autocats doesn't use that sissy Darwinian
gradualism.  This is good old fashioned Goldschmidt
saltationalism.  No ability to fine tune, but when you do
advance, you REALLY advance.  It is all macroevolution!
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