[asdlfj2sd33]

Don't only Caucasians have blue eyes? And aren't they (full disclosure "we" in my case) also the only ones with the mutated version of the gene which controls how much melanin is deposited in skill, hair and... I think also irises? Asians and Africans both have the normal version of the same gene.

And melanin has many roles, sun protection being just one, the other is as a structural protein. Just compare how black skin ages vs. how a redhead of the same (advanced) age looks.

And why would Caucasians have a mutation which deposits less of such a useful protein? Vitamin D.

It is produced when UV light hits the skin. In northern climates with less sun, and skin being covered or you die of exposure, often even when the sun is up, people get a lot less vitamin D.

Inuit get more due to their diet, and modern man also gets much more again because of diet. And yet most people living in the north even today lack vitamin D.

Also, I thought all of the above is common knowledge which makes me question the whole article.

[aaronblohowiak]

"Don't only Caucasians have blue eyes?" No.

More than you ever wanted to know about eyes: http://en.wikipedia.org/wiki/Eye_color

Also, this is neat: A 2002 study found the prevalence of blue eye color among Caucasians in the United States to be 33.8 percent for those born from 1936 through 1951 compared with 57.4 percent for those born from 1899 through 1905.[10] Blue eyes have become increasingly rare among American children with only 1 out of every 6 – 16.6 percent which is 49.8 million out of 300 million (22.4% of white Americans) of the total United States population having blue eyes.[33][34] The plunge in the past few decades has taken place at a remarkable rate. A century ago, 80 percent of people married within their ethnic group. Blue eyes, a genetically recessive trait, were routinely passed down, especially among people of Scottish, English, Irish, Welsh, Western and Northern Slavic, and Northern European ancestry.[33][34][35] In the 1930s, eugenicists[citation needed] used the disappearance of blue eyes as a rallying cry to support immigration restrictions. They went so far as to map the parts of the country with the highest and lowest percentage of blue-eyed people.[citation needed]

[asdlfj2sd33]

From your wikipedia link: Blue eyes contain low amounts of melanin...

Blue eyes are most common in Northern Europe and Central Europe and to a lesser degree in Southern Europe,North America and southern Central Asia; Afghanistan is a notable example.[30] They're also found in parts of North Africa,[31] West Asia, and South Asia[32], in particular the northern areas of India and Pakistan. It can rarely occur as far south as Sri Lanka. However blue eyes are not found within the population of East Asia, due to the major pre-dominance of the brown eye gene in the area.

Central Asians, people from the Caucasus, Afghans, Pakistanis, and even Indians darker then many an African are considered Caucasian. They are Caucasians. And North Africa is full of Caucasians, hell even German tribes, Goths if I recall correctly, settled there during Roman times.

So only Caucasians have Blue eyes. Again because of a gene mutation which control how much melanin is deposited in hair, skin, and irises.

Someone with a lot of melanin could have blue eyes, but they wouldn't appear blue do the the melanin. That's why blue eyes contain low amounts of melanin.

And low amounts of melanin are related to vitamin D, which is related to living in northern climates.

[aaronblohowiak]

"Central Asians, people from the Caucasus, Afghans, Pakistanis, and even Indians darker then many an African are considered Caucasian."

Depends who you ask, as race is purely a social construct.. http://en.wikipedia.org/wiki/Craniofacial_anthropometry

Some mongoloids do have blue eyes, but yes this is a result of interbreeding with descendants of the common ancestor.

[asdlfj2sd33]

It's a bit more then a social construct. The language family is called Indo-European because of shared ancestry.