People with blue eyes may have the same ancestors

A group of scientists tracking genetic variations that led to blue eyes concluded the variation occurred between 6,000 and 10,000 years ago. So before this time humans have no blue eyes.

Hans Eiberg, of the Department of Cell and Molecular Medicine at the University of Copenhagen, said: 'From the beginning everyone's eyes are brown.'

This variation affected the gene called OCA2, which is involved in the production of melanin, the pigment that makes the hair, eyes and skin of humans colored. 'Variations affecting the OCA2 gene in human chromosomes have caused a' transition 'and turned off the function of producing brown eyes.'

The gene transformation was determined to be in a gene adjacent to OCA2. Instead of completely paralyzing the gene, the transition is limited to the extent of reducing melanin in the pupil. Therefore, brown eyes have turned into blue eyes.

If the OCA2 gene is completely deactivated, human eyes, hair and skin will not have melanin; medicine called this case albinism.

Eiberg and his team surveyed DNA through the mitochondria, the energy-generating structure of cells, of individuals living in countries like Jordan, Denmark and Turkey. Genetic material originated from women to be able to track down descendants.

The group focused on the OCA2 gene and the variations related to stopping melanin production.

Depending on the amount of melanin in the pupil, a person may have a brown to green eye color. Brown-eyed people have a significant degree of variation in DNA that controls the production of melanin. But they found that blue-eyed people had only a small amount of melanin variation in their eyes.

Eiberg told LiveScience about discovering that blue-eyed people have DNA sequences associated with similar melanin production.'Of the 800 testers, we only found one person who did not match - but the human eye is blue with a brown iris.'

Eiberg said: 'From this discovery we can conclude that blue-eyed people share a common ancestor. They inherited an identical transformation on the same place in their DNA. '