From where blue eyes mutation backed mysterious look in humans comes from! Simple Answer; Genetic mutation. Scientists have always been curious about what causes eye color to be blue, which gives a mesmerizing look. Originally, we all had brown eyes,” says Professor Hans Eiberg, a Danish geneticist from the University of Copenhagen. The first light-eyed human emerged only about 10,000 years ago. In their study, Eiberg and his team recruited 800 blue-eyed men and women across different countries.
They studied the genes that coded blue eyes in all of these individuals. Researchers were able to conclude that all blue-eyed people had a single common ancestor because so many distinguished individuals, having blue eye color, had the same difference in their DNA . The blue-eye gene has been passed on from parents to offspring and has spread to different geographical regions. Today estimated 20-40% of European people have blue eyes. So what happened?
Before we get into details of how this genetic mutation occurred, let’s first understand how eye color is determined. The color of our eyes is due to the accumulation of melanin in the iris, the structure surrounding the pupil.
Melanin is the pigment that gives color to skin, hair, and eyes of humans.
Specialized cells that produce melanin are called melanocytes, which are stored inside cells in places called melanosomes. Melanin production depends on the activity of the a protein called, P protein. P protein is responsible for giving colors.
It is a key element in the production of melanin. The more the amount of melanin will be in the eyes, the eyes will be resultantly darker in color. If you have high melanin, you’ll have brown eyes. If you have a moderate amount of melanin, you’ll have green or hazel eyes. If you have little or no melanin, you’ll have blue eyes.
Sounds interesting, right ?
So What causes your body to produce little or no pigments? The answer is Genetics!
There’s a specific site on chromosome number 15, that plays a major role in eye color. There are 9 genes that play their roles in eye colors, but the main two genes are known as HERC2 and OCA2. The HERC2 Gene is responsible for activating the OCA2 gene and the OCA2 gene produces a protein that produces pigment. If either of these genes is missing, that will cause disruption in the process. Eventually, a low amount of melanin is produced in Iris with minimum concentration. As a result of that, blue eye color appears because the low level of melanin is not able to produce a darker brown color.
Why are the most blue-eyed people of European descent?
Europe was the epicenter of the blue-eye genetic mutation. Blue-eyed people account for an estimated 8% of the population. However, in Northern European countries, such as Iceland, blue-eyed individuals find themselves in the majority. This might be one of the most important factors to explain the high proportion of blue eyes on the continent.
Another critical hypothesis is the theory of sexual selection. The essence of this concept is that individuals were much more picky in ancestral Europe than anywhere else in the world. In other words, a European guy in those days was more attracted to women with blue eyes than those with brown eyes, because blue eyes were considered an attractive feature. This type of selection might have increased the probability of giving birth to a child with blue eyes. It allowed the genetic mutation to spread, and it also explains the difference in eye color diversity in Europe versus the rest of the world.
So, What’s your eye color?