Did You Know…Everyone with Blue Eyes is Related

Blame it on mutations

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Originally, we all had brown eyes. That’s right: when we were all African, we all had brown eyes.

Blue eyes arose from a single mutation from brown eyes. One baby in Europe or the Near East more than 14,000 years ago was born with blue eyes due to a single mutation. Everyone with blue eyes can be traced back to a single ancestor. Their genetic mutation was inherited at the exact same point.

This mutation turned partly off the ability of one of our genes to produce melanin. Melanin is brown and is the pigment that darkens the eyes, hair, and skin. Diluting melanin in dark brown eyes produces shades of light eyes, such as blue.

No one knows why this occurred; that is the beauty of mutation in the genetic sense. It just happens. We originally all had brown eyes because of the strong sun in parts like Africa. The blue-eyed mutation likely thrived in Europe, where the sun was less intense.

Blue eyes are now present in 70–95% of northern Europeans. Think of blue-eyed gods or goddesses from Scandinavia (we are not sexist here!). Frequencies in southern Europe, across Africa, and in southern West Asia are much lower, at 5–20%.

Many scientists think blue eyes might help, but there’s not much proof. Mutations usually prosper only if they confer a survival benefit. It is one of several mutations, such as hair colour, baldness, freckles and beauty spots, which neither increase nor reduce a human’s chance of survival.

References:

Blue-eyed humans have a single, common ancestor

Why humans evolved blue eyes

Till next time,

Calvin

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