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 ...
My eyes are hazel too (as are my Dad’s and one brothers—Moms were light brown, my sister has dark brown and one brother has blue). Kind of a weird mixed up group. However, I have noticed my particular eye color to be fairly common in friends who are half hispanic/half white.
My Mom’s eyes were brown, but as she got older they got kind of goldy brown. I thought that was odd.
Yes, that is the linkage.
Not a guarantee by any means, but as an example, ARMD is more prevalent in those of northern Europeans extraction, than those of Mediterranean descent. Again, due to differences in retinal, specifically macular, pigment density.
Somehow, somewhere I think there’s a mom, maybe from Maury’s show, just itching to use this to ‘splain’ to the [maybe] baby daddy he’s the one.
I do!
Well, maybe we’re long-lost cousins!
The only thing I know about eye color is that mine are brown and my wife says that is why I am often full of ...well you get the picture.
That’s good to know. My husband has blue eyes as do 2 of my sons, so they should be sure to be checked regularly, I would guess. Thanks for the info.
You have no Idea of the embarrassment when I sit with my family and the only people not Grey or strongly headed that way are me and the grand kiddies.
Oh more than likely! I’m a mongrel, so it could well be. :)
LOL and probably true, yes?
Mom, dad and all my siblings have brown eyes. My grandpa (mom’s dad) had brown eyes but my grandma (mom’s mom) had blue eyes. I have green eyes.
YES! OKden! Two of you...out of how many miuyons and miuyons of people in this primordial soup?
(Life is GOOD!)
Are they green green or hazel? My husband has sort of blue green. Mine have brown in the middle and then green around that.
My eyes are dark blue with the yellow ring. My youngest sister has gray eyes,too.
Yes...I do. I look SO much younger than my brothers that people who don’t know me mistake me for their daughter!!
LOL!
I had very dark brown eyes until I got Pink Eye in December. After using the drops my eyes turned different colors. Sometimes they are green and sometimes they are brownish-green. I wish I had my brown eyes back.
They’re pretty much green green now. Only a tiny bit of brown left. Didn’t really notice it until I saw up close pics of my eyes. But, when I was younger, my eyes would look more green depending on the color clothes I wore. I have mood eyes. LOL!
LOL and you know what green means......
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