Re: Article: Small Molecule Interactions Were Central To The Origin Of Life


"Robert Karl Stonjek" <rstonjek@xxxxxxxxxxxxxx> wrote in message news:e4g2jt$2l99$1@xxxxxxxxxxxxxxxxxxxxxx
Small Molecule Interactions Were Central To The Origin Of Life

In an important new paper forthcoming in the June issue of The Quarterly
Review of Biology, Robert Shapiro (New York University) argues against the
widely held theory that the origin of life began with the spontaneous
appearance of a large, replicating molecule such as RNA. Instead, Shapiro
raises an alternative that does not depend on a "stupendously improbable
accident," presenting the more plausible idea that life began within a
mixture of simple organic molecules, multiplied through catalyzed reaction
cycles and an external source of available energy.

"The diversity of organic chemistry, with its harvest of competing,
interconnected reactions, becomes an asset rather than a liability in the
case of the energy-driven system," explains Shapiro. "The existence of side
reaction paths can provide the network with the capacity of reacting to
circumstances."

Shapiro outlines how replicator theories, though they have been supported by
"prebiotic" syntheses carried out by chemists using modern apparatus and
purified reagents, are highly unlikely. The creation of a molecule that can
self-replicate requires the combination of diverse chemicals in a long
sequence of reactions in a specific order, interspersed by complicated
separations, purifications, and changes in locale.

Instead, Shapiro introduces the idea of a "driver" reaction, linked to a
free energy source, that helps convert an unorganized mixture into a
organized, self-regulated metabolic network.

YES!!! Though this set of ideas is hardly original with Shapiro.
Wachtershauser, Morowitz, and others have said much the same thing.

I have recently commented about the fact that most OOL research is conducted
by organic chemists (like Shapiro, Miller, and Orgel) rather than biochemists.
I have also suggested that the work of the chemists is unrealistic because
it is not informed by a sufficient biochemical understanding of what the end
result must look like (that the chemical OOL process achieves).

It is somewhat embarassing that I also believe that the chemists have mostly
gone wrong by trying to create polymers like proteins and nucleic acids, and
their precursors. It can be argued, I suppose, that in this regard, the
chemists have paid *too much* attention to what the biochemists have told
them.

"If we wish a more plausible origin of life, then we must work with the
assumption that life began, somehow, among one of the mixtures of simple
organic molecules that are produced by abiotic processes," writes Shapiro.
"Nature will be instructing us, rather than we attempting to impose our
schemes onto it."

I'm not sure I would want to endorse this as a research program, if Shapiro
is suggesting that we should try out lots of different mixtures of simple
organic molecules in lots of environments and just see what happens. There
is still something to be said for 'imposing our schemes' if those schemes
are properly informed by an understanding of what modern life is telling
us about its history.

Reference: Robert Shapiro "Small Molecule Interactions Were Central to the
Origin of Life." The Quarterly Review of Biology, June 2006.

Full Text at the University of Chicago via ScienceDaily
http://www.sciencedaily.com/releases/2006/05/060517001538.htm

Posted by
Robert Karl Stonjek

Thx RKS. I look forward to reading Shapiro's review.


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