Jumping genes??

Brian Kwong bkwong at unixg.ubc.ca
Wed May 12 03:25:48 EST 1993


In <93131.204446PXF3 at psuvm.psu.edu> <PXF3 at psuvm.psu.edu> writes:

>Here's the question: What about jumping genes?  Here's the context:  She
>wrote a term paper about "Women in Biology." She has been able to find out,
>using standard reference books, the definition of a jumping gene.  But she's
>stumped on what the connection is to her topic.  If someone could give her a
>name that's relevant, she'll track down the rest (she hopes!).  And her mom
>will learn something, too.

One of the first scientists to appreciate the dyanamism of the genome was
the geneticist Barbara McClintock (your Woman in Biology!), who died in
1992.  In 1947, while performing breeding experiments on maize at Cold
Spring Harbor Laboratory, McClintock saw odd patterns in the the
inheritance of pigments that the convential rules could not explain.
After puzzling over her results, she concluded that a few of the genes did
not have fixed locations on a chromosome.  Rather they seemed to leap from
on spot to another between parent and progeny.  Environmental streeses
such as heat appeared to increase the rate at which such genese transposed
themselves.  Like Mendel's results, McClintock's idea of transposable
genetic elements, often called TRANSPOSONS or "jumping genes," languished
for decades.  Nothing in the one-way flow of information from DNA to RNA
to proteins seemed to allow for the possibility that genese could move.
In the early 1970s, however, McClintock's theory was vindicated.
Molecular biology experiments proved that small pieces of DNA did
sometimes move within or between chromosomes, thereby triggering changes
in gene expression.  By jumping to a site beside or within a gene, for
example, a transposon could shut it off.  McClintock's discovery won her
the Nobel Prize in 1983.


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 B R I A N   W .   K W O N G            |  Internet E-Mail Address:
 University of British Columbia, Canada	|  ~~~~~~~~~~~~~~~~~~~~~~~
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