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Archiver > FERGUSON-DNA > 2008-02 > 1202324552


From: Angus Ferguson <>
Subject: Re: [FERGUSON-DNA] Blue Eyes-Brown Eyes
Date: Wed, 06 Feb 2008 19:02:32 +0000
In-Reply-To: <003d01c868ed$0cb5d480$0401a8c0@deniselaptop>


I have blue - grey eyes, as does my son (thankfully!) but biologically, I'm
probably not a Ferguson! Ahh, the objective reality of genetic genealogy!

Angus Ferguson


> From: Denise Lake <>
> Reply-To: <>
> Date: Wed, 6 Feb 2008 13:21:10 -0500
> To: <>, <>
> Subject: Re: [FERGUSON-DNA] Blue Eyes-Brown Eyes
>
> Just looked it up and for the 4 generations that I can check, we all had
> blue eyes.
>
> How cool is this?
> Denise Ferguson Lake
>
> -----Original Message-----
> From:
> [mailto:] On Behalf Of Sandy Sellers
> Sent: Wednesday, February 06, 2008 11:57 AM
> To:
> Subject: [FERGUSON-DNA] Blue Eyes-Brown Eyes
>
> 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. What
> is the genetic mutation
>
> "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. Limited
> genetic variation
>
> 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 isEye 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."
>
> ============================================================
> FERGUS(S)ON DNA Project website:
> http://freepages.genealogy.rootsweb.com/~colin/Ferguson/DNA/
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> ============================================================
> FERGUS(S)ON DNA Project website:
> http://freepages.genealogy.rootsweb.com/~colin/Ferguson/DNA/
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