Posted on 05/31/2009 1:23:07 PM PDT by SunkenCiv
What most people know about the inheritance of eye color is that brown comes from a dominant gene (needing one copy only) and blue from a recessive gene (needing two copies). University of Queensland geneticist Rick Sturm suggests that the genetics are not so clear. "There is no single gene for eye color," he says, "but the biggest effect is the OCA2 gene." This gene, which controls the amount of melanin pigment produced, accounts for about 74 percent of the total variation in people's eye color.
Sturm has recently shown that the OCA2 gene itself is influenced by other genetic components. After gene-typing about 3,000 people, Sturm found that how OCA2 is expressed -- and how much pigment a person has -- is strongly linked to three single nucleotide polymorphisms (SNPs), or single letter variations, in a DNA sequence near the OCA2 gene. That suggests a more complicated story than the blue-recessive/brown-dominant model of eye color. "For example, among individuals carrying the SNP sequence "TGT" at all three locations on both copies of the gene, 62 percent were blue-eyed," says Sturm's colleague David Duffy. By contrast, only 21 percent of individuals carrying only one TGT copy at each location and 7.5 percent of those lacking the TGT entirely had blue eyes.
Depending on the particular combination of SNPs inherited, a person can have a range of OCA2 activity that lands them on the spectrum between blue and brown eyes. What about green eyes? "Green eyes probably represent the interaction of multiple variants within the OCA2 and in other genes, including perhaps the red-hair gene," Duffy says.
(Excerpt) Read more at discovermagazine.com ...
Famous Heterochromes
Alexander the Great
Anastasius I of the Byzantine Empire
Dan Aykroyd
Kate Bosworth
Michael Flatley
Louis Émile Javal
Mila Kunis
Oded Kattash
Tim McIlrath
Les Murray
Pacho O’Donnell
Max Scherzer
Jane Seymour
Kiefer Sutherland
Christopher Walken
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One of my friends back in the day was Sicilian. His eyes were almost black. I like the coffee reference, though. :)
Mine are pea-green. Iraqis have called me "eyuni bazuna." (Eyes of a cat.)
Go figure.
The daughter of one of my coworkers has cat eyes. Her pupils are vertical slits, similar to those of a cat. When she went up for her physical before joining the Air Force, the doctors thought she was wearing contacts.
Never went back to the doctor, but believe me, I looked at them enough during the Pink Eye to know that they definitely changed color, and it was even obvious to people who know me and they noticed the change. They are not as light as they were after the Pink Eye. I had it in one eye then the other then back to the first one. That stuff nearly killed me! The eye color changed when a friend of mine had it, too.
Recent eye test and there is nothing wrong with my eyes.
Maybe 15 years ago, the Audubon Zoo in New Orleans had some white alligators with blue eyes — really freaky looking!
Wow, that’s cool!
I once saw a picture of a blue-eyed white ferret as well, but now I can’t find it.
They are NOT pea-green, you Moron! They are jade-turquoise (depending on if you’re pissed off or not)...and they are beautiful...
However, they are green and awesome!
My eyes are green as grass.
lol
My Mom was a green eyed red head, my Dad black haired with dark brown eyes.
I was a dark blonde (silver now) with green eyes (bright green like leaves on a tree).
My bro has beautiful hazel eyes that look blue depending on what he wears.
Same here.
*sigh*
Hey you!
Long time no see!
I have seen your beautiful green eyes, and they do NOT look pea green!
They are about the same shade as mine!
My son’s eyes are what his cousin’s wife from Chile called “honey eyes.” Almost a golden color. His dad’s eyes were blue.
And my six sibs ALL had the dark brown eyes of my mother. Not me, though!
Black Lab — the wellspring of the Nation of Islam. /weirdjk
My father had brown eyes and black hair. My mother had grey-blue eyes and brown hair. I have brown/auburn hair and blue-grey eyes.
My paternal and maternal grandfathers had brown/auburn hair and blue or blue-grey eyes.
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