"Men Are From Earth, and So Are Women"

[Lutfi M Hussein]

Hi all,

Below is a related article that appeared in today's
Arizona State University's daily newspaper.

Interestingly, it reports the findings of a researcher
at ASU's Biodesign Institute who has "found" that
women and men are "different" in their perception of
color and color variations. According to the
researcher, women have been favored by nature because
it was women not men who were the primary gatherers in
the hunting-gathering stage of our evolution.

It would be interesting to see how students may
respond to these two articles especially as they
discuss "scientific knowlegdge" and its implications
for social construcionism.

Best wishes, Lutfi


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Weblink:
http://www.asu.edu/feature/color-sense.html

Biodesign Scientist Suggests that Men and Women May
See the World Differently

These photos simulate the degree of difference in
color perception afforded to some women who inherit a
variant form of the red vision gene in addition to a
typical red vision gene. Colors are seen more
intensely and with greater distinction by those with
the normal and variant gene.



Stereotypes about the superior color sense of women
may be rooted in genetics. Brian Verrelli, a
researcher at the Biodesign Institute at Arizona State
University, is co-collaborator on a study suggesting
that natural genetic selection has provided women with
a frequent ability to better discriminate between
colors than men.

The results of the study by ASU’s Verrelli and Sarah
Tishkoff of the University of Maryland, appear in the
upcoming issue of The American Journal of Human
Genetics. Their research focused on the gene that
allows people to perceive the color red; a gene that
is found only on the X-chromosome. They found that the
gene has maintained an unusual amount of variation
that is about three times that of other genes.

“Normally, this degree of genetic variation is
suppressed through natural selection,” said Verrelli.
“In this case, nature is supporting a high degree of
variation instead.”

Verrelli explains that variation in the red gene is
created via the exchange of genetic material with a
neighboring gene that detects green. The scientists
speculate that enhanced color perception was important
when women were the primary gatherers in the
hunter-gatherer phase of human existence. It would
have allowed them to better distinguish among fruits,
foliage and insects. Therefore, nature supported the
variation, despite some negative consequences to men.

Because women have two X-chromosomes, women can
receive one chromosome with the typical configuration
of the red vision gene while the other chromosome
receives a slight variation. It is the combination of
a normal and variant gene, which occurs in about 40
percent of women, that may provide a broader spectrum
of color vision in the red-orange range.

By contrast, men have one X-chromosome, and any
variation in the single red gene that they receive
reduces their ability to distinguish between red and
green. This accounts for the relatively high
percentage of men—8 percent—who have a color vision
deficiency. It was this statistical aberration that
first interested Verrelli in pursuing this research.

“Most detrimental conditions caused by a genetic
variation affect a tiny fraction of one percent of the
population,” Verrelli said. “The fact that the problem
of color-blindness was so common suggested an
important mitigating advantage,” said Verrelli.

While genetic research has traditionally focused on
significant mutations in genes, the research of
Verrelli and Tishkoff suggests that subtle variations
may exist for explicit reasons and are worthy of
attention. This research adds considerably to the
knowledge base on color vision deficiency.

While the common term used is “color blind,” Verrelli
notes that color vision deficiency is the more
appropriate descriptor. Deficiencies are grouped into
three commonly-identified conditions, but within
these, individuals experience varying degrees of color
deficiency.

Our perception of color comes from our ability to
distinguish red, green and blue. The combination of
these three colors forms the basis for all the colors
humans perceive. Other forms of life have differing
systems of color vision, and these distinctions may
help us understand how and when life forms separated
in the evolutionary process.
==================================



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Lutfi M Hussein
lutfi_hussein at yahoo.com
http://www.public.asu.edu/~lhussein/