The people who belong to the select group of humans who have blue eyes can begin to identify each other – a research made with mitochondrial DNA revealed that all of them have a family relation, even if far away.
The conclusion emerged from an extensive research conducted by the Danish geneticist Hans Eiberg, which toured countries such as Turkey, Jordan and Denmark studying the genes of people with blue eyes. He found that a single genetic mutation gave rise to pigmentation, and was also able to locate the event in space and time.
According to the study, the first human in history to acquire this particular color in the iris lived near the Black Sea, about seven thousand years ago, and passed the characteristic acquired from generation to generation. Perhaps this explains the high concentration of blue eyes in Europe and in particular in Eastern Europe. “A genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a ‘switch’ which literally ‘turned off’ the ability to produce brown eyes”, explains the researcher.
The gene controls the production of melanin, the pigment that regulates color as the skin, hair and eyes of mammals. The “switch” did not block completely the creation of melanin (which would lead to albinism), limiting their presence to small amounts and giving rise to blue eyes. Since the variations in individuals with green or hazel eyes occurred more randomly, making it impossible to trace a single occurrence.
There is no evidence to suggest any relationship between the color of the iris and someone health or ability to survive. Originally, before the mutation in the gene OCA2, all mankind had brown eyes.