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Blue Eyed Humans Have A Single Common Ancestor!

As for the genes for Blue and Green eyes, there is a relatively high likelihood that they were inherited from Neanderthals, rather than having emerged independently in Europeans fairly recently. But the Red Haired, Freckled, green and Blue eyed Neanderthals went extinct around 28,000 years ago – long before modern Africoid humans in Europe lost their melanated skin.

Research shows that people with blue eyes have a single, common ancestor. According to some studies, blue eyes may have evolved because these individuals were able to cope better with seasonal affective disorders. The theory is that people with blue eyes may be better equipped to tolerate long periods of low light. Scientists have tracked down a genetic mutation which took place 6,000-10,000 years ago and is the cause of the eye color of all blue-eyed humans alive on the planet today. Blue isn't actually an eye color it is the lack of melanin. Blue eyes are blue due to a lack of pigment. As weird as it sounds, blue eyes aren't really the color blue—they don't contain any blue pigmentation. All eye colors are determined by melanin, which is the same pigment that gives skin its color. The iris only looks blue because of the way light reflects. An eye with less melanin absorbs less light. Collagen fibers in the eye scatter the light, and it reflects off of the surroundings, making eyes appear blue.

"Originally, we all had brown eyes, like our first modern human African ancestors" said Professor Hans 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 color 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, affected human beings would be without melanin in their hair, eyes or skin colour -- a condition known as albinism.

More than 80 variants in the OCA2 gene have been identified in people with oculocutaneous albinism type 2. People with this form of albinism often have light yellow, blond, or light brown hair; creamy white skin; light-colored eyes; and problems with vision. 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 color.

Researchers found a genetic determinant of blond hair in Solomon Islanders.

First, one must note that this is not an isolated feature in Oceania. Rather, blondism crops up in the Solomon Islands, in New Guinea, as well as among some Australian desert groups. This in itself should make us skeptical of the model of European admixture. Additionally, blue eyes, which exhibits a higher frequency in Europeans than blonde hair, is similarly common in these populations.

Melanesian Blond Hair Is Caused by an Amino Acid Change in TYRP1:

Naturally blond hair is rare in humans and found almost exclusively in Europe and Oceania. Here, we identify an arginine-to-cysteine change at a highly conserved residue in tyrosinase-related protein 1 (TYRP1) as a major determinant of blond hair in Solomon Islanders. This missense mutation is predicted to affect catalytic activity of TYRP1 and causes blond hair through a recessive mode of inheritance. The mutation is at a frequency of 26% in the Solomon Islands, is absent outside of Oceania, represents a strong common genetic effect on a complex human phenotype, and highlights the importance of examining genetic associations worldwide. Today, brown is the most common eye color worldwide but after recent photos of the indigenous Buton tribe who are located in the southeast Sulawesi region of Indonesia , taken by geologist and photographer Korchnoi Pasaribu, went viral on social media and puzzled people on how Asians are also born with natural blue eyes.

This is because of a rare genetic disorder called Waardenburg syndrome which causes congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes (or one blue eye and one brown eye), a white forelock, or patches of light skin. The syndrome is caused by mutations in any of several genes that affect the division and migration of neural crest cells during embryonic development. Buton also nown as Butung, Boeton or Button is an island in Indonesia located off the southeast peninsula of Sulawesi. The island is largely covered by rainforest and is known for its wildlife.


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