![]() ![]() So if blue eyes are the result of a genetic mutation in a single individual, how did the trait spread from just one person to being present in 20 to 40 percent of the populations of some European countries today? "They have all inherited the same switch at exactly the same spot in their DNA." "From this we can conclude that all blue-eyed individuals are linked to the same ancestor," said Eiberg. Brown-eyed individuals, on the other hand, have considerable individual variation in the area of their DNA that controls melanin production. In addition to having significantly less melanin in their iris than people with brown eyes, hazel eyes or green eyes, blue-eyed individuals have only a small degree of variation in their genetic coding for melanin production. This genetic switch, located in the gene next to the OCA2 gene, limits the production of melanin in the iris - effectively "diluting" brown eyes to blue. "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."Įye colour depends on the amount of a single type of pigment (called melanin) in the iris of the eye. "Originally, we all had brown eyes," said Hans Eiberg, associate professor in the Department of Cellular and Molecular Medicine at the university and lead author of the study. It appears that a genetic mutation in a single individual in Europe 6,000 to 10,000 years ago led to the development of blue eyes, according to researchers at the University of Copenhagen. All blue-eyed people may have a common ancestor Here are a few facts about blue eye colour you might not know: 1. This is one reason why blue colour contact lenses are popular. Among human beings, blue eyes are less common than brown eyes. ![]()
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