Our look says a lot about us. Is it the same with our eye color?
The color of our eyes is marked by our genes. The study of the color of our eyes is really complex. Previously it was believed that this color came marked by dominant and recessive genes, but today we know that is not so simple. Any small mutation can alter our eyes.
The color of our eyes depends on the amount of melanin pigment in the iris. Blue, gray and green eyes are lighter because they have less melanin in the iris while the dark eyes have much more melanin. This melanin not only gives color to the eyes, it is also an excellent filter against the sun. Because they have less pigment, the light eyes are much more sensitive to the harmful rays of the sun than dark eyes.
Heterochromia is an eye disorder in which the iris is a different color. Heterochromia occurs infrequently and may be congenital or acquired.
The blue eyes could come from a single common ancestor. And scientists place that could be born 10,000 years near the Black Sea as a result of a genetic mutation. This ancestor would be that they come from those with blue eyes. Probably this genetic mutation helped the Europeans to better synthesize vitamin D in a darker and less sunlight environment.
How did this isolated mutation survived? Some theories speak of sex selection, in which males and females choose partners that are unusual. This theory argues that those with blue eyes would be much more attractive. These men and women stuck, increasing the chances of having children.