Page 405 - Carrahers_Polymer_Chemistry,_Eighth_Edition

368 Carraher’s Polymer Chemistry

one can argue about the simplicity and interrelatedness of the design as to origin and the ability
through ordinary evolution to design such complex items as our human eye.
The imprinted region of chromosome 15 contains about 8 genes one of which is responsible,
when broken, for Angelman syndrome—a gene called UBE A. Beside this gene are the two top
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candidates for the Prader–Willi syndrome when broken, one called the SNRPN gene and the other
called IPW.
While these diseases normally occur because of mutation of these genes, it may also occur from
a pair of parental chromosomes failing to separate, with the egg ending up with two copies of the
parental chromosome. After fertilization with a sperm, the embryo has three copies of that chromo-
some, two from the mother and one from the father. While the embryo generally dies, in some cases it
persists. If it persists and it is chromosome 21, then the result is a Down syndrome child. But normally
the body detects the mistake and “kills” one of them. It does so nearly randomly so that there is about
a one-third chance of eliminating the paternal-derived chromosome. Generally there is no problem but
if the tripled chromosome is number 15 then there are two copies of UBE A, the maternally imprinted
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gene, and no copies of SNRPN (or IPW) exist resulting in a Prader–Willi syndrome child. Recently it
has been found that UBE A is switched on in the brain. This leads us to another unfolding saga, that
3
of imprinted genes being controlled “directly” by the brain. In mice, it is believed that much of the
hypothalamus, found at the base of the brain, is built by imprinted genes derived from the father, while
much of the forebrain is built by imprinted genes derived from the mother.
What is intelligence? There are different “kinds” of intelligence. The so-called intelligence quo-
tient (IQ). Intelligence appears to be related to the ability to gain, understand, remember, and relate
information and it is believed that about one half is in some ways related to our genes. So, unlike the
Huntington diseases, while there is a genetic link it is not an absolute link. Several chromosomes
and genes within these chromosomes are beginning to be identified as “smart” genes. One of these

genes, called IGF2R, is found on the long arm of chromosome 6. This gene was first linked to

liver cancer so it shows the variety of capability that may be present within a single gene. IGF2R
is a large gene with the typical exons and introns. Among its varied activities is its involvement in
the metabolism of sugar. One form of this gene is found in greater frequency in supposedly super-
smart people than in so-called average intelligence people. Thus, there appears to be a relationship
between the occurrence of one form of this gene and intelligence. This is circumstantial evidence
at best but it is a start. An interesting side light is the observation that people with high IQs are, on
the average, more effective at metabolizing sugar and that this gene is sometimes connected with
insulin related proteins and the ability to metabolize sugar.
We again must not believe that IQ-related intelligence irrevocably binds us or propels us.
Harvard did a study some time ago where they tried to relate intelligence to success (what ever
success is) and came up with a relationship that success was related to intelligence times the square
of effort.
Learning is related to intelligence. In general, the more apt we are to learn, retain, integrate,
and use information the more intelligent we are. Since our brains are really limited in storage of
information and for other reasons, intelligence requires an interesting mix of remembering and for-
getting, a short range memory and a long range memory. Our input is also mixed. We have a kind

of filtering system that filters out supposedly unwanted input, such as a constant ticking of a clock

or constant hum of the fl uorescent light.
One of the active agents is cyclic AMP. A protein called CREB (for CRE binding protein; CRE
is simply a specific DNA unit, part of a gene, that is called the cyclic AMP response element or site)

is activated altering the shape and functioning of the synapse in our brains when exposed to cyclic
AMP or some related compound in our brains. Genes that are activated are called CRE genes with
the name the initials of cyclic-AMP response elements. CREB, when phosphorylated, binds to the
CREs near certain genes acting as a transcription factor and turning on or activating the genes.
Animals without the CREB producing gene are able to learn but do not possess long-term memory.
It is believed by some that the CREB related genes are in fact essential to our learning and memory

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