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From: wrp@biochsn.acc.Virginia.EDU (William R. Pearson)
Newsgroups: sci.bio
Subject: Re: Creating life
Keywords: Life
Message-ID: <2189@hudson.acc.virginia.edu>
Date: 31 Oct 89 13:51:57 GMT
References: <2461@umbc3.UMBC.EDU> <4516@utastro.UUCP>
Sender: news@hudson.acc.virginia.edu
Reply-To: wrp@biochsn.acc.Virginia.EDU (William R. Pearson)
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Organization: University of Virginia, Charlottesville
Lines: 39

In article <4516@utastro.UUCP> terry@astro.UUCP (Terry Hancock) writes:
]In article <2461@umbc3.UMBC.EDU> cs225202@umbc5.umbc.edu.UUCP (Sang J. Moon) writes:
]>Just a thought... I know that the basic building blocks of DNA can be now
]>created from inorganic molecules, but can biologists use these building blocks
]>to create viable DNA which will cbecome an actual organism?
]>
]	No, as I understand it, there are some problems:
]
]	1. We don't yet have the ability to construct arbitrary 
]	sequences of DNA.  We are limited to a) simple code 
]	sequences (such as all one type, or sets of three, or
]	something) or b) copying codes that are found 
]	naturally.
]		I would be VERY interested in info refuting
]	this statement, if such exists.
]
]	2. Even if we COULD do 1., we don't know enough about
]	molecular biology to make a plan for a viable organism
]	(unless we copy extensively from an existing one).  There
]	is much study left to be done.
]

	It is technically possible to make any DNA sequence you like.
However, most machines that do this are limited to 100 unit pieces,
and living organisms have considerably more DNA.  (The 100 unit pieces
can be linked however.)  To give you an idea of the scale involved,
small viruses have 5000 - 50,000 units (nucleotides) of DNA, large viruses
200,000 - 500,000 nucleotides, E. Coli (our favorite bacteria) 4,000,000,
fruit flies: 80,000,000 (I recall), mammals: 3,000,000,000.  Thus,
it would take a lot of pieces to do it.

	And it is certainly true that we do not know enough about the
genes required to maintain an independent functioning organism to design
the DNA molecule from scratch.  The first complete sequence of an organism,
E. Coli, may be known in the next 2 years.  Once it is known, it would
be technically possibly to synthesize an E. Coli DNA molecule from organic
chemicals, but only by copying the E. Coli sequence.  Even given the
molecule, we do not know how to build an environment for it that would
allow it to be replicated and start making the things E. Coli needs to grow.