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From: ningluo@marvin.cs.Buffalo.EDU (Ning Luo)
Newsgroups: sci.bio
Subject: Re: Creating life
Keywords: Life
Message-ID: <12866@eerie.acsu.Buffalo.EDU>
Date: 7 Nov 89 16:15:19 GMT
References: <2461@umbc3.UMBC.EDU> <12500@cit-vax.Caltech.Edu>
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Reply-To: ningluo@cs.buffalo.edu (Ning Luo)
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In article <12500@cit-vax.Caltech.Edu> wen-king@cit-vax.UUCP (Wen-King Su) writes:
>I have a thought.  Rather than to try and synthesize existing life
>forms, wouldn't it be simpler to synthesize life forms that might have
>existed billions of years ago, when the ocean is just a pool of simple
>chemicals?  Even the most simple, present-day virus is a challenge to
>synthesize. Yet a viron is not really alive until it enters a host that
>provides the viron additional components to allow it to reproduce.  If
>life really came from a pool of chemicals, then there must be an early
>form of life that is very simple in structure, and is capable of
>reproducing itself without a lot of supporting components.  Maybe we can
>make such a life form without too much trouble.
>-- 
>/*------------------------------------------------------------------------*\
>| Wen-King Su  wen-king@vlsi.caltech.edu  Caltech Corp of Cosmic Engineers |
>\*------------------------------------------------------------------------*/

I believe this HAS BEEN ACCOMPLISHED (so-called "evolution in vitro"
experiments by Spiegleman (sp?) and his colleagues.  You can find
the references from M. Eigen's articles a few years back.

However, this is NOT a life form in full sense, since it is required to
supply the nucleotides, high energy molecule source AND the enzyme
(RNA polymerase), just like a viron or a virus dependent on its
host, a living organism, to provides these supplies.

So, before we talk about "creating life", we have to have a clear
consensus about "what is life"?  Or, for the sake of simplicity,
"what is the minimal life"?

The discussion about "what is life" as a scientific question
can very easily metamorphose into a purely metaphysical debate.
To be specific, let's adopt Eigen's view:
Life begins when a set of macromolecules establish an enclosure
of replicating themselves in the presence of only "small" molecules.
"Small" here could mean nucleotides, ATP's, amino acides, etc..

People studying the origin of life are still having a hard time
to find a primordial condition in which the concentrations of the
precursor small molecules could be maintained high enough so that
the polymerizations could take place spontaneously.
But, let's put this issue aside for the moment, and let's assume
that such a condition "somehow" occurred on the primordial earth.
We may never know what this condition exactly is, and may never be able
to re-generate life in the same fashion.   But, we may find other
conditions in which some set of macromolecules could reproduce
themselves from small molecules.  If we achieve this, we can
say: We have created a life form.

Now is the quiz time:
Could the virus or the worms in the computer world
be considered as a life form in a general sense?
After all, this is an "autopoietic" form in a
world of bits and bites.

Luo, Ning
Dept. of Physics  
SUNY Buffalo     
Amherst, NY 14260  |  ningluo@marvin.cs.buffalo.edu      (APARNET)