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From: evs@duke.cs.duke.edu (Ed Simpson)
Newsgroups: sci.bio
Subject: Re: information content of DNA
Message-ID: <9574@duke.cs.duke.edu>
Date: Thu, 30-Apr-87 12:17:36 EDT
Article-I.D.: duke.9574
Posted: Thu Apr 30 12:17:36 1987
Date-Received: Sat, 2-May-87 09:29:44 EDT
References: <2840@ecsvax.UUCP> <11189@teknowledge-vaxc.ARPA> <978@aecom.UUCP> <425@haddock.UUCP> <1010@aecom.UUCP> <430@haddock.UUCP>
Reply-To: evs@duke.UUCP (Ed Simpson)
Organization: Duke University Medical Center, Durham, NC
Lines: 18

In article <430@haddock.UUCP> johnc@haddock.ISC.COM.UUCP (John Chambers) writes:
> ....  It seems
>clear after just a little thought that selection would tend to eliminate
>overlapping genes, perhaps replacing them with replicates that can then
>mutate independently.

Not if the overlapping DNA sequences confer some sort of "coadaptaion".
This would be the case if the DNA sequences coded for proteins that conferred
a higher fitness of the organism than homologous proteins produced by other
DNA sequences.  There's lots of discussion in the literature about the 
possibility of selection favoring increased linkage of certain genotypic 
combinations.  In the case of non-overlapping genes there can never be
100% linkage; there is always the possibility of crossover occuring meiosis.
It seems to me that overlapping genes would be one way of achieving 
essentially 100% linkage.
-- 
UUCP: {decvax, seismo}!mcnc!duke!evs  ARPA: evs@cs.duke.edu  CSNET: evs@duke
Ed Simpson, P.O.Box 3140, Duke Univ. Medical Center, Durham, NC, USA 27710