[asa] Scientists propose the kind of chemistry that led to life

From: PvM <pvm.pandas@gmail.com>
Date: Sat Jun 09 2007 - 14:41:44 EDT

Interesting research was recently announced relating to the origin of life.


 A pair of UCSF scientists has developed a model explaining how simple
chemical and physical processes may have laid the foundation for life.
Like all useful models, theirs can be tested, and they describe how
this can be done. Their model is based on simple, well-known chemical
and physical laws.

The work appears online this week in The Proceedings of the National
Academy of Sciences.

The basic idea is that simple principles of chemical interactions
allow for a kind of natural selection on a micro scale: enzymes can
cooperate and compete with each other in simple ways, leading to
arrangements that can become stable, or "locked in," says Ken Dill,
PhD, senior author of the paper and professor of pharmaceutical
chemistry at UCSF.

The scientists compare this chemical process of "search, selection,
and memory" to another well-studied process: different rates of neuron
firing in the brain lead to new connections between neurons and
ultimately to the mature wiring pattern of the brain. Similarly,
social ants first search randomly, then discover food, and finally
build a short-term memory for the entire colony using chemical trails.

They also compare the chemical steps to Darwin's principles of
evolution: random selection of traits in different organisms,
selection of the most adaptive traits, and then the inheritance of the
traits best suited to the environment (and presumably the
disappearance of those with less adaptive traits).

Like these more obvious processes, the chemical interactions in the
model involve competition, cooperation, innovation and a preference
for consistency, they say.

Paper http://www.pnas.org/cgi/content/short/0703522104v1?rss=1

<quote>We develop a computer model for how two different chemical
catalysts in solution, A and B, could be driven to form AB complexes,
based on the concentration gradients of a substrate or product that
they share in common. If A's product is B's substrate, B will be
attracted to A, mediated by a common resource that is not otherwise
plentiful in the environment. By this simple physicochemical
mechanism, chemical reactions could spontaneously associate to become
chained together in solution. According to the model, such catalyst
self-association processes may resemble other processes of "stochastic
innovation," such as Darwinian evolution in biology, that involve a
search among options, a selection among those options, and then a
lock-in of that selection. Like Darwinian processes, this simple
chemical process exhibits cooperation, competition, innovation, and a
preference for consistency. This model may be useful for understanding
organizational processes in prebiotic chemistry and for developing new
kinds of self-organization in chemically reacting systems.

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Received on Sat Jun 9 14:42:29 2007

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