--- Damien Broderick
<d.broderick@english.unimelb.edu.au> wrote:
> >> > Do you agree that these instincts are built
> into their
> >> > brains by DNA?
>
>
http://www.nytimes.com/library/review/070200genome-review.html
the piece displayed at the above site contains the
following paragraph:
>
> "Can our self-image of fuzzy free spirits long
survive when the genome proves that life, at its
deepest level, is scripted by a logical program? The
program's control is so tight that, as has long been
known, a single error in the instructions can cause
malfunctions such as sickle-cell anemia and other
hereditary diseases"
the image becomes less like a rigidly engineered
machine and more like a free-spirited dance when one
considers transposons, or "jumping genes."
i quote below from
http://latin.arizona.edu/~plpweb/micgen_98/Lect17/Lect_17.htm#tran
"microbial genetics 428 lecture notes"
"In the 1940s, Dr. Barbara McClintock discovered that
certain "regulatory elements" in maize could move from
site-to-site and, by doing so, affect gene expression.
Dr. McClintock's work was initially met with
skepticism and doubt. Ultimately, her work resulted in
a Nobel Prize. However, it was not until ca. 30 years
later that similar mobile genetic elements were found
in bacteria. These genetic elements move at a low
frequency (10^(-7) to 10^(-2) depending on the
element). The movement of these elements can alter
gene expression and in some cases even the
organization of genes within a chromosome. Thus, our
perception of the genome of an organism has changed
and it is now regarded as being fluid rather than
static.
The primary reason for this state of flux is due to
the presence of Insertion Sequences (IS's) and
transposons (Tn's) in the DNA. These mobile genetic
elements were named to reflect the fact that they can
move or "transpose" themselves from place to place in
the DNA. How these transposons "move" around in the
DNA of an organism is fascinating and differs from
normal homologous recombination."
transposons not only move from place to place in the
dna, but are also turned on and off at various times
in the development of a cell.
i do not know of any research concerning the play of
transposons in the human brain, but it seems likely
that such does take place.
nigel hammersted
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