Posted on 11/03/2004 3:34:16 PM PST by blam
Women see scarlet, men see red
Jennifer Viegas
Discovery News
Wednesday, 4 August 2004
The world may appear a more colourful place to women, according to a new study that finds many women perceive a greater range of colours than men, particularly shades of red.
The U.S. study, which analysed DNA from populations around the world, is published in the September issue of the American Journal of Human Genetics.
How men and women see the world appears to relate to evolution and how our early ancestors found food.
Men were likely to have been surveying the landscape for prey to hunt. But the researchers theorise that women were gathering fruits, vegetables, insects and other foods they often identified and rated by colour.
The researchers analysed the DNA of 236 people from Africa, Asia and Europe.
The scientists focused on a particular gene, OPN1LW, which codes for a protein, called an opsin protein, involved in detecting red light.
This gene also exchanges amino acids, the building blocks of protein, with a nearby gene involved in detecting green light.
Within the test group, the researchers found 85 variations of the OPN1LW gene, three times more genetic variation than for any other human gene.
Natural selection
The researchers, led by Assistant Professor Brian Verrelli at Arizona State University, who is also a postdoctoral fellow at the University of Maryland, said the high rate of variation was maintained by natural selection.
"Natural selection could have maintained these genetic differences at the red opsin gene thousands of years ago, and this is why we still see them in a large proportion of people today," the researchers said.
"It is estimated that a number of people today, we estimate about 40% of women, have added colour perception ability; however, it is unclear whether natural selection still operates today to maintain it."
Verelli and co-author Assistant Professor Sarah Tishkoff, from the University of Maryland, said that the X chromosomes could have two types of opsin, one perceiving shades of true red, the other shades within the red-orange range.
Men have one X chromosome and one Y chromosome, so they only have one of the two types of red-detecting opsin.
The limit, and possible problems with amino acid exchanges, sometimes result in colour blindness, which now affects 8% of all men.
Women can possess both opsin pigments because they have two X chromosomes.
According to Tishkoff and Verrelli, the 40% of women who have both pigments have superior colour perception for reds, and possibly other colours. This is because contrast allows humans to distinguish different colours.
But visual skills among the sexes could balance out because the same genes that affect colour recognition might also influence depth perception and visual acuity, which some men could excel at over women.
Tasty meal or poison?
In prehistoric times, colour perception could have meant the difference between eating nourishing foods and deadly morsels.
"The added colour perception would be a benefit to [women] and their offspring if it helps with possibly distinguishing edible berries and fruits from green background foliage, to distinguish ripe fruits from unripe ones, or even to distinguish nonpoisonous plants from poisonous berries," the researchers said.
"This added colour perception may explain how hunter-gatherer techniques became so common in humans."
Since the genetic component of vision does not take into account how our brains process colours, it is possible that every person literally sees the world in a somewhat different way.
Animals, fish, birds and insects may see things even more differently. The researchers said that organisms living in the deep ocean, for example, have several types of blue opsins that enable them to see countless shades of blue.
GGG Ping.
Now I know why there is 10,000 shades of nail polish.
And I own at least 5,000 of them.
I could've told them that and saved all that money. I'm a beadworker and have a massive collection of Japanese seed beads. Including about 30 shades of green, 10 or 12 reds (can't do much with red) 40-some different blues...my husband just gets that long-suffering look whenever I get back from a bead show and start showing him the fascinating differences between two tubes of green beads. :-)
I have always wondered about that.
We are taught our colors so we call something blue because we are told that it is blue. But maybe if you were looking through my eyes you would not recognize blue because it would look different then what you think blue looks like.
I've thought the same myself. My brother asked me the other night how do 'they' know dogs can see in color. "I don't know."
Please FREEPMAIL me if you want on, off, or alter the "Gods, Graves, Glyphs" PING list --
Archaeology/Anthropology/Ancient Cultures/Artifacts/Antiquities, etc.
The GGG Digest -- Gods, Graves, Glyphs (alpha order)
Once in a while I annoy my husband with my theory that one person's "blue" could look purple or green to someone else. Since we can't see through another's eyes; and they have always CALLED that color "blue"...well that's what they see as blue.
He accuses me of thinking too much...LOL.
Women have better senses of smell too.
I think I'm glad I don't know that song. :)
Glad you found your hat, election was successfull, now back to foofoo land. ;)
I guess the people who did this study do not understand one very interesting genetic fact about women. One of the two X chromosomes in women is TURNED OFF, cases where both X chromosomes are turned on leads some serious birth defects.
Knew...ahem... an exotic dancer named DoubleXX Candy near Ft. Jackson in the 70's.
You just explained it all to me.
She had two serious birth defects.
She could see red though (and green, of course!)
Your statement is fragmented, could you please be more detailed.
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