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.
I could have told them for $5.
My mom has brown, my dad had gray. One sister has gray, one has brown and I have deep blue go figure.
Michael Behe said there are no genes for eyes.
Their structure is controlled by mousetraps.
My husband's eyes are normally brown. Several time when he has gotten ill (auto immune) they turn a lovely green.
But I'm relieved when they return to brown. :-)
I have brown eyes. My husband has brown eyes. All our kids have brown eyes. But we both have grandparents who had blue eyes.
My daughter married a green-eyed guy, and their kids have blue eyes.
My son married a green-eyed girl, and their kids have hazel eyes.
My son married a brown-eyed gal, and their kids have eyes so dark they are BLACK.
same here...both my parents had blue eyes, I have a light green, hubby has brown..one son and one daughter have deep blue and one daughter has hazel. hhmmm. Now our new grand daughter has deep blue eyes, when the daughter that had her is the hazel and daddy is dark brown eyes.
I have brown ones. I have an interesting problem. I can't smell red-haired women. Is it that they are sneaky?
What I want to see is a study linking Rh negative blood with blue eye color. Those genes have to be related somehow. Negative blood is geographically peculiar it's not evenly distributed at all, not even across the West.
And where it IS concentrated, there one remarks blue eyes.
Ireland and Brittany are obvious. Less obvious is also a subset of the Berber tribes in the Atlas Mountains of North Africa. Certain of the Berbers are swarthy with blue eyes, a rather shocking combination. The other strange place is among certain Sephardic Jews of Spain and, of course, Israel (though which direction that population flow occurred is much open to question). Blue-eyed Sephardic Jews is a strange thing...the dark-and-light business again, like the Berbers.
Anyway, I would like to see whatever cross-references there are regarding negative blood and eye color. Intuitively, when I think about the negative-blooded people I have known, the correlation is very, very high.
The Berbers are related to the Sa'ami.
O and A blood types are distributed in about equal amounts across Europe. There is a higher % of O type blood concentrated in Wales though.
O and A are, yes, but Rh negative blood isn't.
Rh negative blood is essentially non-existent outside of Europe, a little slice of North Africa, a slice of Israel, and parts of the New World.
Within Europe, it's highest concentration is in the Basque country, with Ireland a close second and Wales and Brittany behind them. Interestingly, there is NOT much of a concentration in the intermediate lands, nor in surrounding Spain, France, Italy, Germany or further East. Not much in England or Scotland, but a lot in Ireland and Wales. (Essentially, this tells us that the trait arrived by boat, and gives a strong boost to the ancient Irish "Milesian" legend, which said that the Irish actually sailed from what is now Spain in a fleet commanded by a leader named Miletus. If that sailing were from the Basque country, it follows a straight line across the Bay of Biscay to Brittany, Wales and Ireland, bypassing everything else.
But then you've got that outcropping of negative blood among a certain Berber tribe in the Atlas Mountains (only), and it's practical non-existence elsewhere. Amongst the Jews is easier to fathom, given their pelerinations and intermarriage over the centuries. Still, it's a RECESSIVE trait, which gives pause.
Anyway, it's a queer thing.
Oppenheimer says that the DNA of the British is ancient, 85% of the Brit's DNA arrived as early as 12k years ago. Now, 9,000 year old, Cheddar Man's (found in the UK) DNA is U5 which is the dominant line of the Sa'ami.
Thank you. :-)
Go Tigers! (I'm from Toledo)
Not so odd. You got a recessive blue gene from one of your parents. Your recessive blue matched up with your husband's blue three times (against the odds, but not hugely so) to give blue-eyed children.
He's had several cycles of color change over the past 30 years.
My grandmother had her ophthalmologist tell her to go to her doctor, based on iris changes, because she had uterine trouble... She had cancer, which they successfully treated with radiation. That was in the late 60's.
There's a whole field of alternative health diagnosis called iridology which analyzes and diagnoses ailments using markers and changes in the iris. I've knows a few New Age folks who swore by it.
So you *are* a Tigers fan, yes??? ;-P
My mother is Rh neg & has brown eyes, so I don't think the traits are linked. Her maternal line was Prussian & her paternal line was half Norwegian, half Swedish. The brown eyes were from the Prussian side.
This still does not genetically explain why brown-eyed people are intellectually superior to blue-eyed people....?
Interesting.
My parents both have green eyes, but my brother has blue eyes and I have some weird color the DMV lists as "grey" but my friends describe as "dirty white" or "ice cube." They are VERY light in color, and I have a VERY dark ring around the iris.
Hubby's folks are green-eyed and hazel-eyed. BIL has green eyes, hubby has light brown.
Both our boys have strangely-colored eyes. Our oldest's are almost orange, while the little one has my whacky color, as does my brother's daughter.
We must have some really wild genetics going on all over the place around here, but I find this topic fascinating. When you have a big extended family such as ours, I love to watch and see where stuff like eye color pops up.
Thanks for posting this,
Regards,
The cancer was noticed because of certain spots in the iris, I think. So no worry there.... ;-)
My kids are determined I'll be a Red Wings fan! I saw the Storm beat the Charlotte Checkers just last week. LOL
Everyone in my extended family have bright blue eyes.
My husband and I have hazel eyes, and were shocked when we produced three blue eyed children. The fourth has brown eyes, and then we were shocked that they weren't blue. :)
Not us...we've got every color in the rainbow. We also have a lot of red hair (my brother and I are both auburn-haired), but neither of our parents are. I've got aunts and uncles on both sides with red hair, and my maternal grandfather was a redhead, but still...that red hair shows up unexpectedly sometimes!
My SIL has one bright blue eye and one eye that is half blue and half brown. Now THAT'S wild looking. It was the first thing I noticed after the surprise of meeting a woman even taller than I am. No red hair, though, poor girl.
Thanks again for the fun thread.
Regards,
Did their daddy have a lot of blue eyes, or do the kids just sorta win and lose 'em, like marbles?
;-)
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