Humans with blue eyes have a single common ancestry.

According to new research, humans with blue eyes share a common ancestry. A research team from the University of Copenhagen has discovered a genetic mutation that occurred 6-10,000 years ago and is responsible for all blue-eyed individuals alive today.

What exactly is a genetic mutation?

Professor Hans Eiberg of the Department of Cellular and Molecular Medicine noted, "Originally, we all had brown eyes." "However, a genetic mutation in our chromosomes affecting the OCA2 gene resulted in the construction of a "switch" that effectively "turned off" the potential to generate brown eyes." The P protein, which is involved in the formation of melanin, the pigment that gives our hair, eyes, and skin colour, is encoded by the OCA2 gene. The "switch," which is found in the gene next to OCA2, does not completely shut down the gene; rather, it restricts its activity to lowering melanin formation in the iris, thereby "diluting" brown eyes into blue. As a result, the switch's effect on OCA2 is quite particular. Humans would have no melanin in their hair, eyes, or skin colour if the OCA2 gene was totally deleted or switched off, resulting in albinism.

Genetic diversity is limited.

The quantity of melanin in the iris may explain everything about the colour of the eyes, from brown to green, although blue-eyed people have very little variance in the amount of melanin in their eyes. "We may deduce from this that all blue-eyed people have a common ancestry," Professor Eiberg explains. "They've all inherited the identical switch in their DNA at the exact same location." Brown-eyed people, on the other hand, have a lot of variance in the part of their DNA that governs melanin synthesis.

Professor Eiberg and his colleagues looked at mitochondrial DNA and compared the eye colour of blue-eyed people in Jordan, Denmark, and Turkey. Professor Eiberg originally indicated the OCA2 gene as being important for eye colour in 1996, and his findings are the latest in a decade of genetic study.

Our genes are shuffled by nature.

The change from brown to blue eyes is neither a positive nor a bad change. It's one of a number of mutations, including hair colour, baldness, freckles, and beauty spots, that have no effect on a person's chances of surviving. "It simply indicates that nature is continually mixing the human genome, building a genetic cocktail of human chromosomes and experimenting with different alterations as it does so," Professor Eiberg explains.