News ID: 128325
Published: 0318 GMT October 05, 2015

Genetic mutation responsible for blue-eyes

Genetic mutation responsible for blue-eyes

A study from the University of Copenhagen reveals that every single person on the Earth had brown eyes until a genetic mutation occurred around 10,000 years ago. Researchers interpret that all people with blue eyes share a common ancestor.

The study examined the DNA of around 800 people with blue eyes from various parts of the world. Out of all of the participants, 99.5 percent had the same mutation in the gene that decides the color of our eyes. In other words, they shared common DNA and were genetically related to one another. The result also reveals that a single person is responsible for this mutation, MedIndia wrote.

Researchers report that a genetic mutation in our OCA2 (ocular cutaneous albinism, form 2) gene resulted in the formation of a switch, which literally turned on our ability to develop blue eyes or turned off our ability to develop brown eyes.

Melanin is a pigment that gives color to our hair, eyes and skin. The OCA2 gene codes for the so-called P protein (melanocyte-specific transporter protein or pink-eyed dilution protein homolog), which is involved in the production of the pigment. However, the switch, which is seen in the gene adjacent to OCA2, cannot completely stop the gene from functioning. Actually, it regulates the action of the gene to reduce the generation of melanin in the iris ― effectively diluting brown eyes to blue.

The switch's influence on OCA2 is very specific therefore. A complete destruction of the OCA2 gene can lead to albinism, which is a genetic condition characterized by the partial or complete absence of pigment in the skin, hair and eyes.

"From this we can conclude that all blue-eyed individuals are linked to the same ancestor. They have all inherited the same switch at exactly the same spot in their DNA" said Professor Hans Eiberg from the Department of Cellular and Molecular Medicine, who is also the lead author of this study.

Resource: MedIndia
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