Re: EXON

17 Dec 2003

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On Wed, 13 Dec 1995, Marc Ramirez wrote:
...
Date: Wed, 13 Dec 1995 00:21:32 -0500 (EST)
From: Marc Ramirez <mrami@mramirez.sy.yale.edu>
To: "Ed Carp (ecarp@netcom.com)" <ecarp@netcom.com>
Cc: Rich Graves <llurch@networking.stanford.edu>,
    High Society List <cypherpunks@toad.com>
Subject: Re: EXON
On Tue, 12 Dec 1995, Ed Carp (ecarp@netcom.com) wrote:
...
...
From:          Rich Graves <llurch@networking.stanford.edu>
(There is some controversy in molecular biology circles as to whether 
"junk DNA" is really "junk" just because it doesn't build proteins. It 
could perform a regulatory or "frame-check" function.)
Actually, I think that once the matter is further studied, scientists 
will discover that the "junk DNA" is not junk, but inactive DNA, 
waiting for a "trigger".
Well, there are a couple of interesting things:
o mutations in non-coding sequences are known to cause certain
    flavors of cancer, and
o the amount of redundancy in exons is rather high in comparison
    to the coding sequences (much like other Exons we know :),
    approaching that of other naturally arising degradation-resistant
    signals, such as human language.
So the signs as of right now are definitely pointing to exons having some 
purpose.  The problem is that exons usually lay outside the start and 
stop sequences, so nobody knows how they are read, which makes it hard to 
give them an interpretation.
folks, say yes to proof reading.

sorry to perpetuate this thread any more but as one of the resident
biochemists/mol biologists i've got an itch to scratch.

in the lines with the single '>' above, you need to replace the word
'exon' with 'intron'.

    exons --> DNA sequences in a gene that (can) yield protein after splicing

    introns --> DNA sequences that are interspersed between exons in a gene

introns have several known roles, including roles in RNA splicing and
RNA editing (a process that sort of skirts the central dogma of 
DNA -> RNA -> protein by changing the 'code' in the RNA).

non-coding sequences represent the bulk of DNA, and for the most part
it's role is unknown although various people have their pet theories.
gene regulation is often carried out by non-coding sequences,
including sequences that are never transcribed into RNA.  thus, they
can be involved in any cancer process.

patrick finerty = zinc@zifi.genetics.utah.edu = pfinerty@nyx.cs.du.edu
U of Utah biochem grad student in the Bass lab - zinc fingers + dsRNA!
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