Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!rutgers!sunybcs!boulder!pell
From: pell@boulder.Colorado.EDU (Anthony Pelletier)
Newsgroups: sci.bio
Subject: Re: evolution by duplication + divergence?
Message-ID: <2568@sigi.Colorado.EDU>
Date: Wed, 14-Oct-87 13:46:15 EDT
Article-I.D.: sigi.2568
Posted: Wed Oct 14 13:46:15 1987
Date-Received: Fri, 16-Oct-87 02:20:24 EDT
References: <369@prlb2.UUCP>
Sender: news@sigi.Colorado.EDU
Reply-To: pell@boulder.Colorado.EDU (Anthony Pelletier)
Organization: University of Colorado, Boulder
Lines: 33
Keywords: brain evolution

In article <369@prlb2.UUCP> ronse@prlb2.UUCP (Christian Ronse) writes:
>divergence of function?
>
>I have read that the paleontologist W.K. Gregory proposed in 1935 (Quart. Rev.
>Biol. 10) that a frequent occurrence in evolution is the sudden replication of
>an existing body part followed by a subsequent elaboration and divergence of
>function of the two parts. Is this suggestion verified?

I can't speak to the evolution of organs, but the model does seem to fit the
evolution of genes.  There are, in eukariotes mostly, gene families.  Different
genes at different loci on the chromosomes that perform different, but very
similar functions.  If one looks at the DNA sequence of these genes, one finds
them to be very closely related.  Examples of these families include the
Tubulin and the Hemoglobin families (|one might even include myoglobin in the
later).  There are also "pseudo-genes" which are non-funtional copies of know
genes, often lacking introns and upstream control regions.  These pseudo-genes
also are often divergent from the parent copy at the DNA sequence level.
These observations as wellas others have led people to suggest that new genes
evolve from old ones by duplication and divergence.
I have a bit of trouble with, say, a prehensile thumb arising first through
a duplication of existing thumbs...but, in other cases, it might work.
>
>I am particularly interested in the case of the evolution of the human (or
>simply primate) brain.
>
>Christian Ronse

Sorry, brain function and evolution is something I try to avoid (+: 
I don't know a thing abut it.

tony
molecular etc. bio.
boulder, co 80303-0347