Blue-eyed Humans Have A Single, Common Ancestor
Wed, 2008-01-30 18:16
#1
Blue-eyed Humans Have A Single, Common Ancestor
Wed, 2008-01-30 18:16
#2
quote:
ScienceDaily (Jan. 31, 2008) — 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.
Read it [url=http://www.sciencedaily.com/releases/2008/01/080130170343.htm]here.[/url]
Wed, 2008-01-30 18:26
#3
rural - Francesca
I wonder if we can go after him for back child support?
Wed, 2008-01-30 19:59
#4
[img]biggrin.gif" border="0[/img] Ol' Blue Eyes had a reputation for not being the most honest of men... but I didn't think he was THAT old.
[ 30 January 2008: Message edited by: martin dufresne ]
Wed, 2008-01-30 21:47
#5
remind
Well, of course the religious right won't recognize this mutation, as it pre-dates their history of creation time line. [img]biggrin.gif" border="0[/img] .
Thu, 2008-01-31 04:00
#6
How do you prevent red eye in photos anyway? EVvery one of my photos where my eyes were actually open for the flash, they're bloody red. Here's what I mean, my Sunday school class from when I was shorter. That's me, third from left with the three shirt buttons. Darn!
[img]http://www.smokingtree.net/images/village7.jpg" width="375[/img]
[ 31 January 2008: Message edited by: Fidel ]
Thu, 2008-01-31 04:56
#7
[img]biggrin.gif" border="0[/img]
What province is Village of the Damned in, anyway?
Thu, 2008-01-31 05:23
#8
rural - Francesca
If it's not near the 401 does it really matter?
Thu, 2008-01-31 07:00
#9
Polly B
quote:
Originally posted by Sineed:
[b] [img]biggrin.gif" border="0[/img]What province is Village of the Damned in, anyway?[/b]
Alberta. It's north of Grande Prairie.
Thu, 2008-01-31 07:05
#10
Red eyes happens when the photographic flash is reflected inside the eyes of subjects. The only way to prevent is is either not to use a flash or - more common - to use a double flash where the first gets the retina to close down, greatly reducing the "red eyes" effect (but making for less impressive horror films).
(Second thought: Should I have taken Fidel's question seriously?...) [img]redface.gif" border="0[/img]
[ 31 January 2008: Message edited by: martin dufresne ]
Thu, 2008-01-31 07:06
#11
I beleive I have relatives there.
quote:
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.
I think that does a decent job of describing those of us with multi coloured eyes as well.
Thu, 2008-01-31 20:25
#12
RevolutionPlease
I knew I was inbred.
Thu, 2008-01-31 20:54
#13
Hey, going back 80 million years, my whiz-kid geneticist/computer scientist nephew is part of the team that established in 2004 that human beings, mice and rats share a [url=http://www.jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=206]c... ancestor[/url] (probably pink-eyed).
You are not alone, Fidel!
[ 31 January 2008: Message edited by: martin dufresne ]
Thu, 2008-01-31 20:55
#14
saga
What about green eyes?
Thu, 2008-01-31 21:07
#15
RevolutionPlease
quote:
Originally posted by saga:
[b]What about green eyes?[/b]
They're lucky. Genes do better with mixing. I said it.
Thu, 2008-01-31 21:08
#16
RevolutionPlease
Can't wait for the jokes. [img]rolleyes.gif" border="0[/img]
Sat, 2008-02-02 07:33
#17
TemporalHominid
quote:
Originally posted by rural - Francesca:
[b]I wonder if we can go after him for back child support?[/b]
assuming the common ancestor is male. 50% chance the ancestor was female.
Sat, 2008-02-02 07:50
#18
rural - Francesca
quote:
Originally posted by TemporalHominid:
[b]assuming the common ancestor is male. 50% chance the ancestor was female.[/b]
Then we need to go after her for child support!
Sat, 2008-02-02 11:36
#19
quote:
Originally posted by saga:
[b]What about green eyes?[/b]
I was wondering that myself. Green eyes run in my family. I have them, my son has them, my mother has them, and her father had them.
Sat, 2008-02-02 13:04
#20
remind
Green eyes are also a genetic mutation. And they may have their own gene.
There is an article linked from the link in the OP that has something about this.
quote:
“But the model of eye colour inheritance using a single gene is insufficient to explain the range of eye colours that appear in humans. We believe instead that there are two major genes - one that controls for brown or blue, and one that controls for green or hazel - and others that modify this trait.“So contrary to what used to be thought, it is possible for two blue-eyed parents to have a brown-eyed child, although this is not common.”
Dr Sturm likens the system to a light bulb.
“The mechanism that determines whether an eye is brown or blue is like switching on a light, whereas an eye becoming green or hazel is more like someone unscrewing the light bulb and putting in a different one.”
[url=http://www.sciencedaily.com/releases/2007/02/070222180729.htm]http://www...