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From: srp@ethz.UUCP
Newsgroups: sci.bio
Subject: Re: information content of DNA
Message-ID: <55@ethz.UUCP>
Date: Sun, 5-Apr-87 10:44:50 EST
Article-I.D.: ethz.55
Posted: Sun Apr  5 10:44:50 1987
Date-Received: Sun, 5-Apr-87 23:41:56 EST
References: <2840@ecsvax.UUCP> <11189@teknowledge-vaxc.ARPA> <978@aecom.UUCP> <2844@ecsvax.UUCP> <7659@ut-sally.UUCP> <425@haddock.UUCP>
Reply-To: srp@ethz.UUCP (Scott Presnell)
Organization: Chem. Dept., Swiss Federal Inst. of Tech. (ETH-Zurich)
Lines: 37

In article <425@haddock.UUCP> johnc@haddock.ISC.COM.UUCP (John Chambers) writes:
>
>One observation I haven't seen yet is the peculiarity of DNA called "reading
>frames"  This effectively triples the number of amino-acid sequences a given
>chunk of DNA encodes.  Multiply this by two for the complementary strand.
>
>Granted, it is very rare that all six readings actually code for something
>in real life.  But this doesn't have much to do with the information content.
>
>It happens with DNA quite often.

Whoa... I can think of only a few cases where two reading frames are used
at one time:  PhiX174, Sv40 (both viruses) come to mind.  I donot know of
*any* cases where more than one reading frame is used at once. Can you
elaborate?

I view the multiple reading frame translation as evolutions' way of dealing
with size problems, thus it happens mainly in viruses (which would like to
be small).  Reading frames do overlap, but not for a very long segment.  It
doesn't take long before one reading frames' Alanine is another reading
frames' Stop codon! The only reason this works at any length is because
the genetic code is degenerate.

As for uses in computer land, I think we are again limited by how difficult
it is to have two strands of information running in the same data space.
On top of that there isn't any data degenaracy to work with in computers.

-- 
-----------

Scott Presnell  Swiss Federal Institute of Technology (ETH-Zentrum)
		Department of Organic Chemistry
		Universitaetsstrasse 16
		CH-8092 Zurich Switzerland.

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