Is "Junk" DNA Used to Provide Genetic Memory
fthornton at ocvaxa.cc.oberlin.edu
fthornton at ocvaxa.cc.oberlin.edu
Tue May 10 10:06:04 EST 1994
In article <graulCpF73w.D11 at netcom.com>, graul at netcom.com (Rick Graul) writes:
>fiddick at lifesci.lscf.ucsb.edu (Laurence Fiddick;x2791) writes:
>>In <graulCoz9Hq.ILx at netcom.com> graul at netcom.com (Rick Graul) writes:
>>>The purpose of "junk" DNA,
>>>as I understand it, is to provide a reservoir of elements
>>>which can be used by the organism for creating new genes.
>>i'd be interested in any references you might have on the purpose of junk dna.
>>presumably there is some cost to carrying junk dna, and i somehow find it
>>hard to believe that natural selection can maintain it for such uncertain
>>long term interests--so any refs on this or any other arguments for the
>>adaptive value of junk dna would be appreciated.
It is obvious that you do not understand the basics of how evolution
works. It would be a good idea to find a good into bio textbook and
read it for the parts on evolution. In fact, junk
DNA could hang around with no problem. Evolution doesn't have a mind
and attempt to find the 'best' solutins. As long as the junk DNA
doesn't inhibit reproductive success, there is no strong pressure t
to get rid of it. "Presumably ther is some cost" is a big presumption.
Even if ther is a cost, it needs to be a cost on reproduction in order
to have an effect on evolutin. Be careful... 'natural selection' doesn't
have a mind and intentions. It doesn't attempt to maintain anything for
'long term interests'.
>Here's the medline entry for the paper where I first saw this idea.
>Search request: F PA GOULD # AND KW JUNK DNA
>Search result: 1 citation in the Medline database
>Type HELP for other display options.
>1. Brosius J; Gould SJ.
> On "genomenclature": a comprehensive (and respectful) taxonomy for
> pseudogenes and other "junk DNA".
> Proceedings of the National Academy of Sciences of the United States of
> America, 1992 Nov 15, 89(22):10706-10.
> (UI: 93066312)
> (PE title: Proceedings of the National Academy of Sciences of the
> United States of America.)
>Abstract: Genomic nomenclature has not kept pace with the levels and depth of
> analyzing and understanding genomic structure, function, and evolution. We
> wish to propose a general terminology that might aid the integrated study
> of evolution and molecular biology. Here we designate as a "nuon" any
> stretch of nucleic acid sequence that may be identifiable by any criterion.
> We show how such a general term will facilitate contemplation of the
> structural and functional contributions of such elements to the genome in
> its past, current, or future state. We focus in this paper on pseudogenes
> and dispersed repetitive elements, since their current names reflect the
> prevalent view that they constitute dispensable genomic noise (trash),
> rather than a vast repertoire of sequences with the capacity to shape an
> organism during evolution. This potential to contribute sequences for
> future use is reflected in the suggested terms "potonuons" or "potogenes."
> If such a potonuon has been coopted into a variant or novel function, an
> evolutionary process termed "exaptation," we employ the term "xaptonuon."
> If a potonuon remains without function (nonaptive nuon), it is a
> "nonaptation" and we term it "naptonuon." A number of examples for
> potonuons and xaptonuons are given.
>graul at netcom.com
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