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…
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.
This isn’t a positive or negative mutation, of course. Not that the fact will prevent the ignorant from value judgements.
Like, how you interpret the headline for this post.
Seafred, Your mom didn’t overcome anything. She passed on the recessive gene because its all she had, while your dad clearly had the recessive gene and passed it on to 3 of his 4 boys. The point of this article, though, is a common ancestor who had the mutation and is the progenitor of all peoples with blue eyes. However, if he was the only one with the gene, given our understanding of recessive genes it should have disappeared *Unless* others had the same mutation. Meaning there is not one common ancestor but many.
I have been doing some DNA testing with Family Tree DNA and in the National Genographic study. I believe we will know a lot more about this when all the latest data is in. NGeo has tested over a hundred thousand indigenous people all over the world and many like myself have put our own in the pot. I am of Viking stock and that is clear. It will take private individuals sharing data to find out what genes we share. DNA testing for ancestry is pretty new and many that take the test still don’t wish to talk about their finding in the gene department, but that will change in time. The DNA studies should put this to rest in the future with out a lot of speculation. I think??
ok this is how it happened i know cuz i went back in time yesterday and watched it if you have a male blue eyed man call him 1 he breeds with fem brown call her 2, now there kid is 3, he breeds with another fem brown 4 both kids have blue gene ok now back then incest wasnt tabbo it was needed due to low population they have a kid 5 there kid now has blue gene due to double resesive gene !! bang that is it now 3 breeeds back to 1 and you got tripple blue witch would make blonde blue eye ther eis your answer ok straight from me a ten year old kid try to find a flaw in my logic i dare you !!
of course we are all mutations. we all come from the a-sexual hermaphrodite to the x and y. mutation simply means change. without change, one cannot evolve. therefore, two blue-eyed blonde haired humans cannot evolve.