- Topics
- Aerospace
- Animals
- Anthro and Archaeology
- Bio and Medicine
- Brain and Behavior
- Business and Economy
- Computers and Electronics
- Education and Outreach
- Energy and Environment
- Geoscience
- Internet and Communication
- Media and Entertainment
- Nanotech, Chem and Materials
- Physics and Numbers
- Security and Defense
- Software
- Space
- Transportation
- Reader Blogs
- Shameless Commerce
- Register/Login
All blue-eyed humans have common ancestor
New research shows that people with blue eyes have a single, common ancestor. A team at the University of Copenhagen have tracked down a genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blue-eyed humans alive on the planet today.
“Originally, we all had brown eyes”, said Professor Eiberg from the Department of Cellular and Molecular Medicine. “But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a “switch”, which literally “turned off” the ability to produce brown eyes”. The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin. The “switch”, which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris – effectively “diluting” brown eyes to blue. The switch’s effect on OCA2 is very specific therefore. If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour – a condition known as albinism.
Variation in the colour of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes. “From this we can conclude that all blue-eyed individuals are linked to the same ancestor,” says Professor Eiberg. “They have all inherited the same switch at exactly the same spot in their DNA.” Brown-eyed individuals, by contrast, have considerable individual variation in the area of their DNA that controls melanin production.
Professor Eiberg and his team examined mitochondrial DNA and compared the eye colour of blue-eyed individuals in countries as diverse as Jordan, Denmark and Turkey. His findings are the latest in a decade of genetic research, which began in 1996, when Professor Eiberg first implicated the OCA2 gene as being responsible for eye colour.
Nature shuffles our genes
The mutation of brown eyes to blue represents neither a positive nor a negative mutation. It is one of several mutations such as hair colour, baldness, freckles and beauty spots, which neither increases nor reduces a human’s chance of survival. As Professor Eiberg says, “it simply shows that nature is constantly shuffling the human genome, creating a genetic cocktail of human chromosomes and trying out different changes as it does so.”
Submitted by BJS on Wed, 2008-01-30 16:14.
- Printer-friendly version
- 35168 reads

Both parents have blue eyes, but none of the children have. Why?
Could this be becuase of a genetic mutation? or is therwe an other reason?
red hair and
I have brown eyes the color of my shit.
blue eyes
i am blue eyes with ondulatory hair.my modher and father are brown eyes with ondulatory hair.
i have blue eyes and blonde curly blonde hair
and baby if your out there i love you mmmmmmmmmmmmmmmmmmmmmmm ya
wow life is strange
ya i notice alot of thing's with blue eyes i have green blue eyes i think actor's or hollywood has a very strang obsession with the whole deal and the world i don't know crazy world.
get a paternity test
get a paternity test
I have blue eyes
I have blue eyes and both of my parents have dark brown hair and eyes(Dad-full blooded italian, Mom-full blooded german). My son has brown eyes and my daughter has crystal bright blue eyes, that a lot of people would love to have. Their dad has one blue eye and one brown eye. How does that work? I guess I just have a VERY MUTATED family! Just call us TMNT!
"First of all, thank you for
"First of all, thank you for answering my question. If only one person started with the mutation, that would mean that two of his/her offspring or descendants would have mated to spread the recessive gene, so that it would actually manifest itself as blue eyes?"
If you're right about this inbreeding, then does that mean that the original blue-eyed person was living in West Virginia?
Blue?
I have blue eyes, my mom has brown and my dad has blue- My husband has brown, his mother has brown and his father has bright blue- what are the chances we will have blue eyed children?
Follow up from non-scince person
First of all, thank you for answering my question. If only one person started with the mutation, that would mean that two of his/her offspring or descendants would have mated to spread the recessive gene, so that it would actually manifest itself as blue eyes?
Brown or Blue?
My moms eyes are blue, and my dads eyes are brown. Since brown is dominate does that mean something's up? Dont flame me im a child ;P
Blue eyes recessive?
I am a Louisiana Creole (African/French/Spanish/Native AMerican)whose family consists of blue-eyed blonde Scandinavian looking persons. With persons of mixed heritage you never know what you will get. Some of my blue-eyed cousins do not even have a parent or grandparent with lightcolored eyes so in my opinion, blue eyes are not necessarily recessive.
Ancestor hailed from Europe
CBS Sunday Morning show did a piece about this new discovery about the Blue Eyed gene and its ancestor. They said the ancestor originated from Europe.
Also, just because someone has brown or green or even gray eyes doesnt mean that their children cannot have a totally different either recessive or dominant eye color. The reason for this is learned in biology in highschool. Although someone might be born with brown eyes, somewhere along the line in their family, someone might have green or blue eyes. If that brown eyed person meets someone else who has blue eyes or green eyes, or they could even just be a carrier of blue or green eyes, at least one out of 4 potential children will have green or blue eyes, despite one or both parents having dominant brown eyes. It could be a 25% chance or a 50% chance that one child might be born with blue or green eyes. It all depends on the carrier genes and how strong they are, like if two recessive (which is blue) meet up, they dominate and a child born of them will be blue eyed, but if a dominate brown and recissive blue meet up, brown will dominate and one child born of them will be brown eyed, but if the brown eyes parent has a recessive blue carrier gene, another child born of them will be blue eyed.
Also, this carrier concept applies to other traits such as hair color, whether or not you have a hitch hikers thumb, whether or not you can twist you tongue and height. I am very short as are both of my brother despite having a father of 6'1. Our mother is slightly shorter than we are. So, it seems that somewhere in my father's irish riddled family, there was a dominate short gene that carried on through my father, despite his parents and his sister and brother being tall, and when it met with my mother's dominate short gene (despite her father being 5'9 (with her mother being as short as we), it produces three short children. However, should we, carrying the tall gene, have children with someone who is tall and or carries the tall gene with them as we do, at least one child will be tall.
It does seems confusing, and perhaps someone else could have explained better, but that's the best I could do at the moment. :D
Hope that helps. Byee!
For non-science person
Blue eyes came to dominate in certain areas because those populations were geographically isolated. This allowed the recessive gene for blue eyes to be expressed with progressively increasing frequency within a limited population. Unlike early Christian paternalism, primitive Scandinavian cultures have traditionally allowed females to choose their own spouses. No doubt, blue-eyed women preferred to mate with blue-eyed men, as is still the case today. Over time, even a slight preference for blue on blue pairings would have resulted in a progressively increasing percentage of blue-eyed people.
Occam's Razor
Science prioritizes simpler explanations to more complex ones. A neutral mutation at one site in many different people, given the current set of facts, can be explained by having a single mutation, so why go with two?
This is known as the principle of parsimony. It explains why, when you lose your wallet, you don't look on the moon. Instead, you look at where you've been. Because a scenario where you lost your wallet where you've been is much more probable than the one in which it ended up on an extra-terrestrial body.
Scientists aren't the only one's who use the principle of parsimony. It's a good practical heuristic. Not always true, but choosing between a simple and more complicated hypothesis, we prefer to go with the simpler.
The phenomenon arises not because it's hard to think outside of a linear path. (I can come up with a thousand possible explanations for why something like this happened -- and so can you.) It arises because we like to choose an explanation and with a rational rule.
Neutral mutations may still be prevelant
Motoo Kimura, the evolutionary biologist who developed the neutral theory of gene mutation, showed that you don't need selective advantage to become pervasive. Some neutral genes increase in frequency to become universal, some neutral genes are just extinguished. It's just a demographic phenomenon.
Also, 10,000 years is a pretty long time (500 generations-ish). Think of the potential number of offspring in that time -- Starting with one couple, assuming each generation averaged 2 kids per generation, that's 2 to the power of 500 more people than are on the planet (by a lot). Not to diminish they're importance, but there really aren't that many people with blue eyes.
Last note, be careful about using words like dominance in this context, since it's a term of art.
non-science person
How did blue eyes come to dominate in certain areas if there was only one common ancestor and blue is a recessive gene?
How can this be?
It's still a bit vague about who this common ancestor is. My dad's family is from Sicily and we all have blue eyes. My irish cousins all have blue eyes too.
So someone 10,000 years ago was quite the traveling ho! LOL.
i was wondering when you
i was wondering when you were going to post physical descriptions of every member of your family...
in terms of eye color, blue,
in terms of eye color, blue, green, hazel, yellow, etc. are all the same thing. Instead of "blue eyes" they could be saying "light-colored eyes"
Blue Eyes
I was told brown eyes are dominant. My father had brown eyes, my mother blue. How many offsprings would my mother have to give birth to before me and sister who both had blue eyes were outnumberd by brown eyed syblings?
chuckwash@aol.com
Blue eyes
I have the most beautiful blue eyes ever...almost like a turquoise color - very unique...I have been complemented on it a lot. I am of Friesen (Northern Holland descent) on both side of my parents. Both my parents have blue eyes. My mothers' mother had brown eyes while her father had blue. My dad's mother had blue eyes while his father had brown. I have six other siblings and they all have blue eyes. I am very fair and blonde. My mom's brother who has brown eyes married a dutch brown eyed women. Three of their kids are brown eyed, brown haired, and one boy is very blonde with blue eyes. Just very interesting how genetics plays a role here...I married a German green-eyed man and my oldest son has green eyes and brown hair, while my younger son has blue eyes, very fair skinned and blonde.
I suspect a joke.
*woosh*
give the guy a break
ok he did a study! wahoo..! i think it explains a lot. and if brown eyed people (such as myself) are to stupid to realize the difference between gene codes and being adopted then you shouldn't be reading this should you!
Oh for crying out loud, tell
Oh for crying out loud, tell me that you did not just introduce Jungian garble into a discussion about allelic frequencies and phenotypic expression. Heck why not throw some Freud in there while you’re at it, genetic reduction in the amount of melanin produced as a conversion disorder!
You’d think after 150 years the days of you people giving the rest of behavioral psychology a bad name would be over. Maybe you can bring Phrenology back as a discipline if you try really hard! :)
/facepalm
dominance without selective advantage?
"Also it's pretty common to call something "neutral" when it has no direct adaptive value even when it *is* strongly selected for by sexual selection (the phenomenon which drove the evolution of the brilliantly flashy but anti-adaptive peacock tail)."
That doesn't make sense. Peacock tails (or blue eyes) aren't "anti-adaptive". If there's sexual selection inferring some advantage towards reproduction and passing on your genes, i'd say it's adaptive! I think it's interesting he's found the specific mutation and estimated the time line, but i think the rest of what he's saying about it being a neutral mutation is complete crap.
Mom had brown dad had blue all teh kids are diffrent colors
My mom has brown eyes. My dad has blue. The first kid my sister had blue. I was second i have hazel they sorta change between blue gray and green. The third kid my brother has bown. the next kid my brother had brown. And the last kid my sister had brown. I did notice that my sister first born with blue eyes has blondish brown hair. I had cold black hair(I had the indian gens in me show more) and darker thicker skin. Tan easy. The rest of the kids with the brown eyes all had started out with blondes hair and as they aged it turn to dark brown. I wonder if the hair color and eye color have any thing to do with each other.
positive
i think this study is very interesting and am certin in the future we will dicover what the true meaning of this trait is. im not one for science, never really did it for me. though i will say there are some facts that cant be ignored. im not of a specfific religon but i think we will find in the far off future that this trait has significant bearing in the world of religon.
compasion and empathy gone awrye...
i think as Carl Jung speperated the human race with his studies that this may very well play into his "theories" as he would praise HSP (highly sensitive persons) and i quote "condemn them in the next. At the same time, their differentness is not visible, potentially
increasing the sense of carrying a secret and being an imposter while others think
they are “normal” due to their persona skills, already described."
um..
youre an idiot
Recessive genes
As far as recessive genes go, blue is recessive to all others. Green being recessive to brown but dominant to blue. As for why your brother and you both have green eyes I cant say. Also in respect to the yellow eyes; because of the large degree of variation in the genes for brown eyes it is possible that they simply have a variation in their genes that causes a shade of brown much lighter that what we would normally perceive as brown, more of a yellow.
Please explain this I am very curious
I have dark brown eyes. My dad has honey brown eyes. My mom has almost black eyes (She is Filipino). My dad's parents both had dark blue eyes. My mom's parents both have almost black eyes. My husband has blue eyes his parents and grandparents all have blue eyes. Both of my children have blue eyes. Can anyone tell me how this can be? I get confused and I had Biology as a freshman in college.
Blue eyes don't always start out blue
Some people are born with brown, green, or hazel eyes that fade to blue as they age. To me this suggests that the genetic changes responsible for introducing blue eyes may be varied. Some people with blue eyes may be born without the requisite melanin and others may have experienced a rapid loss of the pigment, even pre-natally. Since blue eyes can be caused either way it seems more than one genetic variant could be at work.
Green Eyes
I thought green eyes were the result of yellow fat deposits in blue eyes. So if you and your sibling have green eyes, and your parents have blue eyes, it's probably because you're fat.
dominance without selective advantage
The gene for blue eyes might co-occur with some other gene (better ability to tolerate the cold, for instance), and might dominate a gene pool simply by piggy-backing on that other gene which *is* selected for.
Also it's pretty common to call something "neutral" when it has no direct adaptive value even when it *is* strongly selected for by sexual selection (the phenomenon which drove the evolution of the brilliantly flashy but anti-adaptive peacock tail).
In short, blue eyes could have dominated via sexual selection alone.
Neutral mutation - not bloody likely
wonder why the author makes the point that blue eyes are a neutral mutation - going from a single individual to complete dominance over a large geographical area (Nordic countries) in 10,000 years doesn't sound like the result of genetic drift to me.
I'm with the last comment
I'm with the last comment there. It is very likely for the mutation to repeat itself on multiple non-related incidences and not have to stem from ONE person.
It is still hard to think outside of the linear path and consider that nature is very dynamic and more like a multi-to-multi system than a one-to-many system.
fooling around
Sounds like mom was fooling around...
That's really helpful. Why
That's really helpful. Why do you even bother posting if you're not going to be constructive or helpful?
Learn basic manners.
One common ancestor???
Is there not a possibility that "a genetic mutation affecting the OCA2 gene" could have occured at another time and place, meaning that there would be more than one ancestor?
Wrap that rascal
If that distant ancestor had utilized a condom-like device we wouldn't have to put up with those blue-eyed devils today in the land of La Raza.
Back to Europe you foreign devils. La Raza is taking back our land.
This is the age of the Chicano/a and you white devils will be shoved out.
Not disagreeing with the
Not disagreeing with the other comments made---some I downright agree with. …But when will the rest of the scientific fields take the time to know what the hell they are talking about? There isn’t anything magical about genes, they are nothing more than instructions for coding proteins.
The nearly infinite factors that influence this protein production aside, eye color isn’t some binary, digital trait. It’s not like the pigment is 1) on 2) off…and there are so many cells in the iris that are responsible for color—each one may be governed by a different gene or set of genes for that matter. Remember the Afghani girl on the cover of National Geographic? Like that.
Get over yourselves, act more like scientists and less like tabloid journalists.
so?
who cares, people having a cry cos they don't have blue eyes, ohhh im not special cos i'm not mentioned on a science blog, why don't i have blue eyes?? so on so forth. Doesn't mean you're adopted.. but then one can't rule that out. relax a bit. it's interesting stuff though. especially to a blue eyed person such as myself. be good if they could pin point where the ancestor hailed from.
Wait... so does that mean...
Wait... so does that mean... if two blue eyed people get married... is that incestuous of them?
"I met a person with light
"I met a person with light yellow eyes - almost like lemon flesh, without a hint of blue or even green."
Quite striking, isn't it?
http://en.wikipedia.org/wiki/Eye_color#Amber
"Also, isn't it possible that some brown-eyed people may also have the same blue-eyed ancestor?"
Obviously, many do. The article doesn't state otherwise.
Saying that 'all blue eyed people share a common ancestor' is NOT the same thing as saying that 'only blue eyed people share this common ancestor'. There is no exclusion implied.
Of course you are. The
Of course you are. The article *only* states that all blue eyed people share a common ancestor. No where is the claim made that people with brown/green/etc eyes, can not also be descended from this person.
um.
learn basic biology.
Blue eyed people have common
Blue eyed people have common ancestor, but all the descendants of that ancestor don't have blue eyes.
About green eyes.
Just a quick tidbit on green eyes.
Melanin is not the only pigment that colors our features. There is another one, though I forget its name, that codes for a more yellow color, while melanin codes for a brown color. It is thought that green eyes, more unusual eye colors, red and blonde hair are made by interactions of these two pigments.
Answer to brown dominant / blue recessive question.
Blue eyes are still recessive to brown. Picture this: Every cell has a pair of each gene, though they are not always identical pairs (simple genetics). If one member of the pair codes for brown and the other codes for blue, brown still appears. The reason: the gene coding for brown eyes will produce enough of the pigment protein on its own that it overrides the lack of pigmentation the blue-eye gene copy would normally cause in the absence of the brown-eye gene. That is why both member of the gene pair coding for eye color must code for blue for that trait to appear. Otherwise, brown will override.
Now, if only one individual was the original carrier of the blue eye mutation, non of his/her immediate offspring would have blue eyes. But think of this: the blue eye gene, though not represented, still had a normal chance of staying in the gene pool through many, many, many generations. It would have stayed hidden, masked behind the dominant brown eye trait. Finally, numerous people carry this masked gene, and when two of them finally mate, WHAM-O, you are starting to get a population of blue eyed individuals.
Also, brown eyed people most certainly could be related to this original blue eyed person. However, you cannot be certain of this relationship unless you have blue eyes or have family with blue eyes. I have blue eyes, but both my parents have brown. I am related to the blue eyed progenitor and so are my parents.
re: what about green eyes?
All blue-eyed people are descendants of this person; that doesn't mean they're the only ones.
Blue is a recessive trait
You can carry the blue eyes trait and still have brown or green eyes, ie. you can still be related to the original blue-eyed person. What this study is saying is that if you see someone with blue eyes then they are definitely related to the "common ancestor"... if they don't have blue eyes then you can't be certain of their ancestry because they could still be a carrier.
Blue is a recessive trait
You can carry the blue eyes trait and still have brown or green eyes, ie. you can still be related to the original blue-eyed person. What this study is saying is that if you see someone with blue eyes then they are definitely related to the "common ancestor"... if they don't have blue eyes then you can't be certain of their ancestry because they could still be a carrier.
you were adopted
you were adopted
Does not say only blue eyes
It does not say blue-eyed people are the ONLY descendants of this common ancestor. All blue-eyed people do share this ancestor along with people with other eye colors as well.
clearly, you and your
clearly, you and your brother are adopted.
what about green eyes?
OK what about green eyes? Am I not the descendent of the ancestor that my blue-eyed sisters and brother are? Something's being left out here....
and green eyes? - I did not get it
Me and my bro have green eyes. Both our parents have blue. Dad's eyes were bright dark blue and mom's are light milky blue.
You write:
"Variation in the colour of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes."
It makes it sound that green eyes are grouped with brown eyes while blue eyes stay apart. It also makes it sound that blue is the underlying color of the iris overlayed with brown by melanin. I met a person with light yellow eyes - almost like lemon flesh, without a hint of blue or even green. There must be more to the eye color than your article implies.
Also, isn't it possible that some brown-eyed people may also have the same blue-eyed ancestor? 30 years ago it was believed that brown color was dominant and blue recessive - has it changed with this new piece of knowledge?
Post new comment