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Is "Junk" DNA Used to Provide Genetic Memory

Rick Graul graul at netcom.com
Sat May 7 01:52:44 EST 1994

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.

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.

Rick Graul
graul at netcom.com

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