New research shows that blue-eyed people have a single common ancestor

New research shows that people with blue eyes have a single common ancestor. A team at the University of Copenhagen has identified a genetic mutation that occurred 6 to 10,000 years ago and is responsible for the eye color of all blue-eyed people alive on the planet today.

What is a gene mutation?

Professor Hans Eiberg from the Department of Cellular and Molecular Medicine said: 'Initially, we all had brown eyes, but an inherited mutation affecting the OCA2 gene in our chromosomes led to to creating a "switch" that could "turn off the "ability to generate brown eyes".

Blue-eyed people only had a small change in the amount of pigment in their eyes.

The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives our hair, eyes, and skin color. However, the "switch" located in the gene adjacent to OCA2 does not completely turn off the gene, but instead restricts its activity in reducing the production of the pigment melanin in the iris - which "dilates" brown eyes to blue. effectively. Therefore, the effect of the switch on OCA2 is very specific. If the OCA2 gene has been completely destroyed or turned off.

Limited genetic variation

The change in eye color from brown to green can all be explained by the amount of pigment in the iris, but blue-eyed people have only a small change in the amount of pigment in their eyes. . Professor Eiberg said: 'From this we can conclude that all blue-eyed individuals are related to the same ancestor. They all inherited the same switch in the same place in their DNA.' In contrast, brown-eyed people had significant individual variation in the area of ​​DNA that controls their melanin production.

Professor Eiberg and his team examined mitochondrial DNA and compared the eye colors of blue-eyed people in countries as diverse as Jordan, Denmark and Turkey. His discovery is the latest in a decade of genetic research, which began in 1996, when Professor Eiberg first suggested that the OCA2 gene is responsible for eye color.

Nature shuffles our genes

The brown-to-blue mutation is neither a positive nor a negative mutation. It's one of a number of mutations like hair color, baldness, freckles and beauty spots, that don't increase or decrease a person's chances of survival. As Professor Eiberg says: "it simply shows that nature is constantly shuffling the human genome, creating a genetic mix of human chromosomes and trying to experiment with various changes such as so".