21 replies to this topic

[Lazarus Long]

In an interesting finding about blue eyes it appears that the trait must have added to mate attractiveness because it appears that all humans with blue eyes can be traced to one single ancestor and their offspring were so desirable that the mutation spread not only through Europe but much of the world in less than 10,000 years

Genetic mutation makes those brown eyes blue
Scientists find that blue-eyed individuals have a single, common ancestor

By Jeanna Bryner

updated 2:01 p.m. ET, Thurs., Jan. 31, 2008
People with blue eyes have a single, common ancestor, according to new research.

A team of scientists has tracked down a genetic mutation that leads to blue eyes. The mutation occurred between 6,000 and 10,000 years ago, so before then, there were no blue eyes.

The mutation affected the so-called OCA2 gene, which is involved in the production of melanin, the pigment that gives color to our hair, eyes and skin.

"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," Eiberg said.

The genetic switch is located in the gene adjacent to OCA2 and rather than completely turning off the gene, the switch limits its action, which reduces the production of melanin in the iris. In effect, the turned-down switch diluted brown eyes to blue.

If the OCA2 gene had been completely shut down, our hair, eyes and skin would be melanin-less, a condition known as albinism.

"It's exactly what I sort of expected to see from what we know about selection around this area," said John Hawks of the University of Wisconsin-Madison, referring to the study results regarding the OCA2 gene. Hawks was not involved in the current study.

Baby blues
Eiberg and his team examined DNA from mitochondria, the cells' energy-making structures, of blue-eyed individuals in countries including Jordan, Denmark and Turkey. This genetic material comes from females, so it can trace maternal lineages.

They specifically looked at sequences of DNA on the OCA2 gene and the genetic mutation associated with turning down melanin production.

Over the course of several generations, segments of ancestral DNA get shuffled so that individuals have varying sequences. Some of these segments, however, that haven't been reshuffled are called haplotypes. If a group of individuals shares long haplotypes, that means the sequence arose relatively recently in our human ancestors. The DNA sequence didn't have enough time to get mixed up.

"What they were able to show is that the people who have blue eyes in Denmark, as far as Jordan, these people all have this same haplotype, they all have exactly the same gene changes that are all linked to this one mutation that makes eyes blue," Hawks said in a telephone interview.

Melanin switch
The mutation is what regulates the OCA2 switch for melanin production. And depending on the amount of melanin in the iris, a person can end up with eye color ranging from brown to green. Brown-eyed individuals have considerable individual variation in the area of their DNA that controls melanin production. But they found that blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes.

"Out of 800 persons we have only found one person which didn't fit — but his eye color was blue with a single brown spot," Eiberg told LiveScience, referring to the finding that blue-eyed individuals all had the same sequence of DNA linked with melanin production.

"From this we can conclude that all blue-eyed individuals are linked to the same ancestor," Eiberg said. "They have all inherited the same switch at exactly the same spot in their DNA." Eiberg and his colleagues detailed their study in the Jan. 3 online edition of the journal Human Genetics.

That genetic switch somehow spread throughout Europe and now other parts of the world.

"The question really is, 'Why did we go from having nobody on Earth with blue eyes 10,000 years ago to having 20 or 40 percent of Europeans having blue eyes now?" Hawks said. "This gene does something good for people. It makes them have more kids."

So cousins what shall we make of this?

It is not the race of white people, we are the race of blue eyes versus the brown eyes.

[caston]

I was born with blue eyes and blond curly hair but as I have got older my hair has darkened. I have bleeched it a few times but I don't like the
"fake look" it gets nor do I like the effect is has by damaging my hair and hair follecules. I think really the ideal solution would be someway to methylate the genes responsible for hair coloring e.g. MC1R

http://www.gnxp.com/...ves/000889.html

The big pharma solution could be to offer a pill that will make you go blond or even stop you from going grey.

Keeping this on topic sometimes people may wish to change their eye color. Now I wonder what I would look like with green eyes!

Edited by caston, 01 February 2008 - 06:00 AM.

[Shannon Vyff]

Since I had blue eyes, I wanted children with blue eyes--surprisingly I was always quite selective in choosing blue eyed partners for my actual breeding partners (Two). I dated other guys, even had an African American boyfriend from my advanced placement literature class in high school--he and I were very well suited, but for some reason I never thought of marrying him.... When I found my husband off of match.com a year and a half ago, I searched by eye color--for blue or green. So I'm planning on having more children, the three I have already are blue eyed and red haired--I can't wait to see what my new ones will be like , my husband has blue eyes--so I'm assuming that they likely will too. I'd love to do a genetic history mapping of my DNA.

As I've gotten older, I've realized that my feeling that there will be no blue eyed people in 500 years, and that my offspring will have better societal chances if they are 'good looking' -- I've realized all this is not completely true-- so much more about success has to do with temperament and ability, also I would not care if my children had mixed-race babies, I'd love them--and work on enlarging their minds and awareness (what I now think is much more important than looks )

[lunarsolarpower]

I wanted children with blue eyes

Must be one of those darn "selfish genes."

What can I say though? Everyone in my immediate family has blue eyes.

[dr_chaos]

So cousins what shall we make of this?

Wait. Does that mean all the blue eyed girls are my cousins? Then I did some really disgusting things in my life.

[Lazarus Long]

Wait. Does that mean all the blue eyed girls are my cousins? Then I did some really disgusting things in my life.

I must say, being blue eyed myself, I sympathize with your plight.

nevertheless

Finally, someone who gets my jokes.

[icyT]

Well, we're all related anyway... if they mean that people sharing a specific gene of a good consistancy are more recently related, then I guess so...

So should I be nicer to blue-eyed people because they're family or something? Lol.

[Shannon Vyff]

They say you are more attracted to those that look more like you (in countless studies trying to determine what certain genders find attractive in the opposite sex)... makes sense--seems to hold true for what guys I'm more 'instantly' attracted to when I meet them.

[Lazarus Long]

Actually I think to evolutionary scientists the importance of this is not only to highlight how mutational evolution is still occurring in our species in recent times but more to explain the mechanism for the dissemination of such mutations.

I also want to emphasize to those that might want to find a way of *eliminating * all mutation that is simply another example of the relative benign or even the possibly *irrelevant* character of many mutations. In this case however it made some members of the population more desirable sexually and this related to more offspring and a breeder bias.

[niner]

They say you are more attracted to those that look more like you (in countless studies trying to determine what certain genders find attractive in the opposite sex)... makes sense--seems to hold true for what guys I'm more 'instantly' attracted to when I meet them.

I thought guys were attracted to girls like their moms, and girls were attracted to guys like their dads. That would explain a lot of, umm, curious couplings. And people tend to look like their parents.

[icyT]

I don't think this is consistant in all cases. I am heavily attracted to many who look nothing like me.

I think it has more to do with who you marry, settle down and have kids with. People do this around people they feel comfortable with and understand. People who are different than you are sexy as heck erotic and you are amazed by them, but you might have trouble relating in some cases being intimidated or alienated by their strange awesomeness.

[maestro949]

People with Blue Eyes = Mutant Freaks

I also want to emphasize to those that might want to find a way of *eliminating * all mutation that is simply another example of the relative benign or even the possibly *irrelevant* character of many mutations.

Laz - I don't think anybody (sane at least) really wants or cares to eliminate all mutations, just those that are deleterious and lead to suffering. With that said though, it's likely that numerous proteins produced by our DNA are quite suboptimal due to the many mutations that occur over time because as you state, most mutations indeed are rather insignificant. I can envision a day though where we're fine tuning each and every gene/protein combo for even more optimal efficiency. By the time we have that level of knowledge though, we may have already discarded the whole mess of biology and replaced it with a superior design of interchangeable parts.

[Lazarus Long]

Maestro to be fair I was aiming the comment at some of our less *sane* members.

I think a few could come to mind from recent discussions.

I couldn't agree more with the rest of your comments.

With that said though, it's likely that numerous proteins produced by our DNA are quite suboptimal due to the many mutations that occur over time because as you state, most mutations indeed are rather insignificant. I can envision a day though where we're fine tuning each and every gene/protein combo for even more optimal efficiency. By the time we have that level of knowledge though, we may have already discarded the whole mess of biology and replaced it with a superior design of interchangeable parts.

I will add that it is no small irony that Godwin already made it into the Blue Eyed thread and the reason I made the comment is that it is high time that those of us interested in *rational eugenics* begin to establish the sane position on what that means and reintroduce the discussion to those who have made it impolitic to even mention.

We are talking about eliminating genetic diseases from the general population and even improving immune response, perhaps intelligence and physical characteristics over time. However we are not associated with the irrational, classical and bias based *racial and ethnic cleansing* position of the less *sane* advocates. The type of eugenics we are talking about is to save lives never to take them.

There are no *culprits* (victims) to be found within living populations to be eliminated, only advantages offered to future ones and remedies for ailments suffered by the living. You don't make modern *rational eugenics* function through oppression of any kind but rather by building better and more progressive, advanced healthcare and making it available to more and more of the total population.

[maestro949]

I couldn't agree more. Unfortunately there are those that view every step of scientific progress as a slippery slope towards some horrific abuse of improved knowledge and technology.

[Shannon Vyff]

I couldn't agree more. Unfortunately there are those that view every step of scientific progress as a slippery slope towards some horrific abuse of improved knowledge and technology.

Ditto.


Don't know if the following RoboWatch has its own thread, and it almost deserves one if not, but it is inline with your comment very succinctly:


http://www.robowatch.org/main2.html

[dangerousideas]

They say you are more attracted to those that look more like you (in countless studies trying to determine what certain genders find attractive in the opposite sex)... makes sense--seems to hold true for what guys I'm more 'instantly' attracted to when I meet them.

I am sure that you will find the following book, which examines the origin of emotions from an Evolutionary Psychology perspective, interesting:

http://www.theoriginofemotions.com/

Among other remarkable claims/insights the author says that:

1. Men seek novelty in their sexual partners because this increases genetic diversity.
2. Both men and women have greater natural affection - and seek out partners - who remind them of their mothers (but not their fathers).

All in all, this is a fascinating read, and very likely to surprise you with some of its observations/claims.

[Shannon Vyff]

Wow, I so don't agree with quotes listed on the book's home page that you provided--and found it doubly funny to see the silly 'children lose their mother's 'love' at 33 month remark', listed in the first review up at Amazon, among a pretty long litany of people who also found the book more humorous than factual. http://www.amazon.co...0/dp/1419627457

There are many studies and even books that look at evolutionary psychology in a different light, including the recent view that people started long ago, forming long term monogamous arrangements in order to increase their own and their offsprings survival.

I don't even have the time to list all the points of rebuttal that are needed -- to point out why that book is wrong an many counts. Here though is a site I've loved for years that has reviews of Evolutionary Psychology books. The recommended reading list is awesome, the reviews exemplary! http://www.evoyage.com/index.htm

This is a newer site started in 07, it does not have the great input of man who runs the other site--but its peer reviewed academic journal structure is quite useful but has a ways to grow: http://www.jsecjournal.com/

[dangerousideas]

I don't even have the time to list all the points of rebuttal that are needed -- to point out why that book is wrong an many counts.

I did say that the author's claims were "remarkable". Obviously, as a self-published work it is what it is. Normally, I would not waste my time on something without references or an author track record. Occasionally, however, I find it fruitful to venture out of the mainstream to see what kinds of ideas are out there that might alter my perspective about things that I am pretty sure that I understand. I am prepared to give the author the benefit of the doubt and assume that he is aware of how odd some of his conclusions seem, relative to peoples ordinary personal experiences (or perceptions of those experiences).

I did actually read the book, and spent a lot of the time wondering where in the heck the author got some of his ideas. Unfortunately, there are no footnotes, references, or endnotes to back up anything that he claims. As a work on it's own, using the authors own definitions, it appears to be a more or less orginal effort to postulate from first principles how things "Must Be" based upon evolutionary principles, and by and large the conclusions do seem to be internally consistent. Whether or not they are consistent with observations of actual humans in the wild is another matter.

To be charitable, I would suggest that the author is suggesting his own theory about how human beings would behave emotionally if all that was guiding them were evolutionary pressures, without modulation by social norms and conventions. To me, that is "interesting", even if it is not authoritative or conclusive.

[mike250]

Wow, I so don't agree with quotes listed on the book's home page that you provided--and found it doubly funny to see the silly 'children lose their mother's 'love' at 33 month remark', listed in the first review up at Amazon, among a pretty long litany of people who also found the book more humorous than factual. http://www.amazon.co...0/dp/1419627457

There are many studies and even books that look at evolutionary psychology in a different light, including the recent view that people started long ago, forming long term monogamous arrangements in order to increase their own and their offsprings survival.

I don't even have the time to list all the points of rebuttal that are needed -- to point out why that book is wrong an many counts. Here though is a site I've loved for years that has reviews of Evolutionary Psychology books. The recommended reading list is awesome, the reviews exemplary! http://www.evoyage.com/index.htm

This is a newer site started in 07, it does not have the great input of man who runs the other site--but its peer reviewed academic journal structure is quite useful but has a ways to grow: http://www.jsecjournal.com/

looks like the evoyage takes on an already biased view.

[Luna]

My eyes are pretty much the darkest of browns hmm.. I wonder what are the implications of that, other than the actual color.

[Ben]

My eyes are pretty much the darkest of browns hmm.. I wonder what are the implications of that, other than the actual color.

Well for one thing they're better protected against the sun with the increased amount of melanin.

This is anecdotal, but I have a friend whose eyes are a very light blue. He can't go anywhere without sunglasses because even a little sun light hurts his eyes.

[Luna]

That's funny, I am pretty light sensetive.