Posted on 02/25/2007 4:34:29 PM PST by blam
University of Queensland
Date: February 25, 2007
No Single Gene For Eye Color, Researchers Prove
Science Daily — A study by researchers from The University of Queensland's Institute for Molecular Bioscience (IMB) and the Queensland Institute of Medical Research is the first to prove conclusively that there is no single gene for eye colour.
Says Dr. Rick Sturm, the IMB researcher who led the study: "... the model of eye colour inheritance using a single gene is insufficient to explain the range of eye colours that appear in humans. We believe instead that there are two major genes -- one that controls for brown or blue, and one that controls for green or hazel -- and others that modify this trait." (Credit: Image courtesy of University of Queensland)
Instead, it found that several genes determine the colour of an individual's eyes, although some have more influence than others.
“Each individual has two versions of a gene, inheriting one from each parent, and these versions can be the same as each other or different,” Dr Rick Sturm, the IMB researcher who led the study, said.
“It used to be thought that eye colour was what we call a simple Mendelian recessive trait - in other words, brown eye colour was dominant over blue, so a person with two brown versions of the gene or a brown and a blue would have brown eyes, and only two blues with no brown could produce blue eyes.
“But the model of eye colour inheritance using a single gene is insufficient to explain the range of eye colours that appear in humans. We believe instead that there are two major genes - one that controls for brown or blue, and one that controls for green or hazel - and others that modify this trait.
“So contrary to what used to be thought, it is possible for two blue-eyed parents to have a brown-eyed child, although this is not common.”
Dr Sturm likens the system to a light bulb.
“The mechanism that determines whether an eye is brown or blue is like switching on a light, whereas an eye becoming green or hazel is more like someone unscrewing the light bulb and putting in a different one.”
The study was carried out to clarify the role of the OCA2 gene in the inheritance of eye colour and other pigmentary traits associated with skin cancer risk in white populations, and examined nearly 4000 adolescent twins, their siblings and their parents over five years.
The findings are published in this month's edition of the American Journal of Human Genetics, and were supported with grants from Australia's National Health and Medical Research Council and the United States of America's National Cancer Institute.
"Very Clever, Grasshopper"
Gene, Gene The Dancing Machine must have something to do with this. (any Gong Show fans?)
That dance alone was worth $516.32!
interesting...but...
i have brown eyes. my dad has brown eyes and my
mom has hazel eyes.
pat has blue eyes. his parents both have blue eyes.
all three of our kids have... blue eyes!
odd...
IOW, that kid be yours after all.
The surgery simply removed the pigment on the front of the lens.
They are returning to green although the formerly "black ring" is at present only a "brown ring".
I'd always thought it odd to see someone with one green eye and one blue eye. Now I know the secret.
Neither of my parents has green eyes. One has bright blue and the other brown. My kids have light hazel with a black ring ~ the ring didn't form until they were 9 or 10 years of age.
What dolor eyes did the mailman have? :)
mailman???
um, i'm the one with brown eyes. and trust me,
i was there. ;) the kids all have their daddy's
blue eyes.
wow, interesting!
i had laser surgery to correct my vision
about 8 yrs ago. i don't think my eye
color was affected tho.
Did the postman ring once or twice?
Same situation in my family. Dad brown-eyed, Mom blue-eyed, but Dad carried a blue recessive gene. Of their six kids, only one...that would be me...came out with brown eyes. Four had blue eyes and one had hazel.
You are not alone! :-)
Pardon, but my kids are MINE. No doubt there.
see, i've always thought that too, i'm not sure,
but i think the article said something different.
they compaired the genetics to a lightbulb. brown
eyes vs. blue eyes is one lightbulb and hazel/green
is a different lightbulb.
Laser surgery should have no effect. Cataract surgery is much more robust. The eye is sliced further and the contents of the corneal sac are removed ~ the lens, debris, stuff, and pigment (if there was pigment in there).
My eyes change color occasionally. Explain that one! No; I don't wear contact lenses.
well, patton just peered at my peepers and said
they're the same eyes he's been looking at for
some 30 years or so. :)
1. Build up of heme in the bloodstream;
2. need for blood dialysis;
3. you're from Kentucky, named "Harris" and have blue skin (which is real ~ and treatable).
This is very interesting, thanks for posting. My eye color looks very much like the one in the center. Green with a dark outline and brownish around the pupil. But up until I was about 9 they were a deep blue with the dark outline. Curiously, both my parents have/had blue eyes, my mother's were very startlingly light blue, and 3 of my grandparent's had brown eyes. My mother's parents both had brown with flecks of green. My siblings have blue and gray eyes.
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