Scientists are still speculating about when the mutation occurred and blue eyes appeared in a person, but some signs indicate that this most likely happened several decades ago. During this period, there was a massive settlement of Europe, as agriculture from the Middle East began to spread to European countries.
Origin
Human Genetics magazine published a note by scientists that the mutation that caused the appearance of blue eyes most likely occurred in the northwest of the Black Sea region.
Professor Eiberg noted that the "default" color of human eyes should be brown. Dark blue eyes are the result of a mutation, because the dark skin pigment - melanin, affects the appearance of brown-eyed babies. However, in Northern Europe, the OCA2 gene underwent a change that disrupted the production of melanin in the iris, resulting in the color blue.
Professor Eiberg pointed out that everyone had brown eyes at first, but a mutation in our chromosomes of the OCA2 gene caused a "transformation" that "turned off" people's ability to produce brown.
In the iris, the amount of melanin varies, and thereforebrown shades are different. Blue eyes are people who had a common ancestor who changed the gene. They all inherited the same mutation in their DNA.
Blue-eyed men and women have almost identical genetic sequences in the part of the DNA molecule responsible for eye color.
Professor Eiberg has analyzed the DNA of more than 800 people, from white-skinned blond Scandinavians to people with dark skin but blue eyes, living in Turkey and Jordan. His experiment confirmed the hypothesis of a single common ancestor.
It is not clear why blue eyes are more common among the population of the South of Russia and Northern Europe. Previously, it was assumed that this feature gives a certain advantage in summer white nights or polar winters. Maybe this is considered more attractive and therefore most favorable for sexual selection.
Features
Anatomically, the iris includes the ectodermal and mesodermal layers. How the pigment is distributed in them determines the color. Chromatophores are distributed in the mesodermal layer, they contain melanin. The posterior layer contains many pigment cells filled with fuscin.
The fibers and vessels of the iris also play a role.
The main light colors are blue, cyan and grey.
The ectodermal layer has a dark blue color. If the outer fibers of the iris have a low density and low melanin content, then high frequency lightabsorbed by the mesodermal layer, and low-frequency light is reflected from it. Blue eyes are the result of such refraction.
There are people who dream of changing their natural color to blue. They believe that the look will acquire beauty, depth and richness. Most often, blue eyes are considered attractive, photos of blue-eyed people can be decorated using some programs, in particular, Photoshop. By experimenting with computer effects, you can choose the right make-up and cosmetics for yourself.
