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By Peredo |

I´ve read in some different places that scientists have found that all humans with blue eyes are all descendants of ONE single person that lived some 8,000 years ago.

This is to say, that in the same way that it´s been proved that we are all descendant of a genetical "Adam" , and a genetical "Eve", similarly all blue eyed persons in history are all descendants of one single human being whose DNA experienced a mutation resulting in the blue color in the eyes.

For some time I asumed it was just a fact , an interesting fact for that matter, but on second thought I´ve started to think that there´s a lot of misinformation in the media and that it should be better to ask someone more documented about DNA real facts and findings, so I would be thankful if Armando gives us his opinion on the subject.

Best regards for all !

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Armando

8 years 11 months ago

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Hello Peredo,

This what we know so far -

The primary determinant of blue eye color in present-day Europeans is the derived allele G in the SNP rs12913832 in the gene called HERC2. It was found in 100% of the European Mesolithic Hunter-Gatherer specimens that they have sequenced so far according to a pre-print of an academic study from this year by Mathieson et al. which can be found at http://biorxiv.org/content/early/2015/10/10/016477 The ancient Mesolithic Hunter-Gatherers are from Spain, Sweden, Luxembourg, and Hungary from about 7,000-8,000 years ago. Since there are no older specimens that have been found that have been sequenced with rs12913832 we don't know for sure when it first appeared in humans. Mutations can happen independently in people but it is doubtful that HERC2 happened in different people so the Europeans with rs12913832 most likely descend from that person.

The SNP rs12913832 was very uncommon in Anatolian Neolithic which is where the Early European Farmers come from and they started to show up about 7,000 years ago in Europe with different autosomal DNA, Y-DNA (mainly G2) and a different culture. http://dienekes.blogspot.com/2015/11/neolithic-farmers-from-greece-and…

At one time it was thought that blue eyes in Europe came from farmers but now we know that isn't the likely cause.

Armando, it was interesting to me your response regarding blue eyes. Years ago, a physician/scientist told me that all people with red hair are related. Since he was very respected at John Hopkins and the University of Chicago, I took it as truth. Is there truth in this as well? Thanks!

I would love to read Armando's response,  although I am on all nuestros ranchos mailing lists
(I just verified this on the site), I only receive snips .  Was he referring to what I've read that the blonde hair and
blue eye mutation occurred only about 10,000 years ago?
Thanks and please get me back into the fold.
Alice Blake
--------------------------------------------
On Fri, 12/4/15, sarod77@hotmail.com wrote:

Subject: [Nuestros Ranchos] Blue eyes how about Red Hair
To: general@lists.nuestrosranchos.org
Date: Friday, December 4, 2015, 1:53 PM

Armando, it was interesting to me
your response regarding blue eyes. Years
ago, a physician/scientist told me that all people with red
hair are related.
Since he was very respected at John Hopkins and the
University of Chicago, I
took it as truth. Is there truth in this as well? Thanks!

When i did 23 and me i found out i have the genes for color eyes and red
hair. But i have brown eyes and dark brown hair. I do get red hair rigth
before they turn to white hair-

Jose Luis Zambrano De Santiago "El Euforia".

On Fri, Dec 4, 2015 at 10:40 PM, Alice Blake wrote:

> I would love to read Armando's response, although I am on all nuestros
> ranchos mailing lists
> (I just verified this on the site), I only receive snips . Was he
> referring to what I've read that the blonde hair and
> blue eye mutation occurred only about 10,000 years ago?
> Thanks and please get me back into the fold.
> Alice Blake
> --------------------------------------------
> On Fri, 12/4/15, sarod77@hotmail.com wrote:
>
> Subject: [Nuestros Ranchos] Blue eyes how about Red Hair
> To: general@lists.nuestrosranchos.org
> Date: Friday, December 4, 2015, 1:53 PM
>
> Armando, it was interesting to me
> your response regarding blue eyes. Years
> ago, a physician/scientist told me that all people with red
> hair are related.
> Since he was very respected at John Hopkins and the
> University of Chicago, I
> took it as truth. Is there truth in this as well? Thanks!
>

Jose Luis,

You probably have AG for rs12913832. See https://www.23andme.com/you/journal/eyecolor/overview/

This is what it says for AG (only one allele is G, inherited from one parent)

"In Europeans, 56% chance of brown eyes; 37% chance of green eyes; 7% chance of blue eyes."

This is what it says for GG (both alleles are GG, inherited from both parents)

"In Europeans, 72% chance of blue eyes; 27% chance of green eyes; 1% chance of brown eyes."

This is what it say for AA (G not inherited at all)

"In Europeans, 85% chance of brown eyes; 14% chance of green eyes; 1% chance of blue eyes."

Even though having G for SNP rs12913832 isn't a guarantee that a person will have blue eyes only 1% of the Europeans with blue eyes don't have G for SNP rs12913832. No other gene is as common in people with blue eyes. That is why G for SNP rs12913832 is the primary determinant of blue eye color in present-day Europeans.

As far as the red hair, just having two variants of MC1R gene isn't a guarantee of actually having red hair but all Europeans with red hair have the gene from both parents even if neither parent had red hair, in which case it is a recessive gene in both parents. https://www.23andme.com/you/journal/red_hair/overview/

Using a personal situation is anecdotal and is a common cause of logical fallacies.

Thank you Armando for your information and to all that added to the conversation.

This topic has been of interest because in my extended family from both paternal and maternal there were twins on both sides with red hair from flaming to Strawberry blond. On my paternal side one brother of my fathers' had children with red flaming to strawberry blond while the rest had blond blue eyes. In both sides of the families none has appeared again only green eyes except for the uncle whose children had the blue eyes some grandchildren did have blue eyes but no red hair.

Thank you so much Armando for your comprehensive answers!

My question was really triggered after a conversation with a very good friend of mine who is a tall, blonde,blue eyed lady.
She is the daughter of a very dear friend of mine who died 13 years ago and whose parents were French; her mother is from mexican descendence.

This ladys father was tall,blond, blue eyed while her mother has dark brown eyes.

Her maternal grandfather (her mexican branch) was also a blue eyed gentleman.

Well in that conversation I told her that we happened to be relatives , and her answer was : " are we related through the Ayalas?" (Her maternal lastname), and I answered : "Not only through the Ayalas but through the Audiffreds"

Of course she couldn´t understand how could we be relatives through her fathers branch since he was French; then I told her about those genetic findings I read.

Right then and there I started thinking that I could have been lying, that maybe what I read was not a real fact but one more false "information" available in the web.

Now from what I see, all blue eyed persons are JUST PROBABLY related through one individual who had a mutation over 8,000 thousand years ago, but that particular mutation could eventually have happened in more than just one individual; am I correct ?

Alice,

I responded to a question about blue eyes and I mentioned the SNP rs12913832 which is the primary determinant of blue eye color in present-day Europeans. We don't know when SNP rs12913832 first arose but it is at least 8,000 years old based on the DNA analysis of a specimen from Loschbour, Luxembourg from that time frame. It could have happened as far back as 12,000 years ago but since there aren't enough ancient specimens there is no way to have an accurate range of dates as to when it happened. All of the European Mesolithic Hunter-Gatherers have the SNP rs12913832 and that culture seems to have started about 12,000 years ago. Something else to consider is that there are more Mesolithic than Paleolithic specimens that have had DNA sequencing so, although unlikely, SNP rs12913832 could have appeared in that culture.

Blonde hair is due to other mutations and is harder to predict. The Mathieson et al. paper doesn't address the results of those mutations probably due to the difficulty of predicting them and some of the specimens having low coverage of the DNA.

I don't know if all people with red hair are related but in order for people with European ancestry to have red hair both parents have to have the MC1R gene variants, even if recessive, along with other unidentified modifiers. Everyone with the MC1R gene variants most likely do descend from a common person that first had those variants.

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