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A mutation occurred in the genetic code of a person in the Black Sea region 10,000 years ago, leading to the majority of blue-eyed people today having the same mutation. The mutation disrupted the production of melanin in the iris, turning brown eyes blue. The reason for the spread of blue eyes is unknown, but it could be due to sexual preferences or other evolutionary causes.
Early humans all had brown eyes. Then, a mutation occurred in the genetic code of a person, probably someone who lived in the northwestern part of the Black Sea region about 10,000 years ago. A 2008 study by researchers at the University of Copenhagen determined that the same tiny mutation in the gene that determines eye color is present in about 99.5 percent of blue-eyed people today, indicating a link to a single ancestor.
Why you might have bablues:
Scientists theorized that the mutation occurred during a period of rapid population expansion in Europe following the spread of agricultural activities from the Middle East.
Brown is, essentially, the “default” color of human eyes, linked to the buildup of the dark pigment in the skin called melanin. The OCA2 mutation disrupted the production of melanin in the iris, turning brown eyes blue.
It is not known why blue eyes spread among the population of northern Europe and southern Russia. It could be that the trait was thought to be particularly attractive and played a role in sexual preferences. Or there could be other evolutionary causes.
