Where Do We Get Our Eye Color?
There’s more to it than the DNA of our parents.
Most of us learned what we know about eye color from a chart shown in biology class in elementary school. According to this chart, the children of the two parents with brown eyes will also likely have brown eyes; If two blue-eyed parents are destined to be, there are mostly blue-eyed children. The table may contain minor color codes, exact percentages, and linear inheritance lines. But the inheritance story of eye color is much more complex (and unpredictable) than we’ve been taught.
Why do eyes look different colors?
People get their eye color from melanin, a protective pigment that also determines their skin and hair tone. The fact that melanin is good at absorbing light is of particular importance in the function of the iris, which determines how much light enters our eyes. When light passes through lenses, most of the visible light spectrum goes to the retina, where they are converted into electrical signals and translated into images by the brain. A small portion that is not absorbed by the iris is reflected back and what we see in the form of eye color occurs.
Now this color depends on the type and amount of melanin innate in the person. There are two types of pigments. These are eumelanin, which creates a rich chocolate brown color, and amber, which creates a green and hazel color. Meanwhile, shades of blue eyes are formed by containing relatively small amounts of eumelanin. When the amount of this pigment is low, it diffuses the light around the anterior layer of the iris, causing the shorter blue wavelengths to reappear. This makes the color blue an example of what is called the “structural color”. Colors such as brown and, to a lesser extent, green and hazel are defined as “pigment colors”. That’s partly why the sky is blue (thanks to an atmospheric light trick known as the Rayleigh effect).
Green eyes are interesting because they combine two types of pigments with light scattering: They contain slightly more eumelanin and a little more pheomelanin than blue eyes. Hazel eyes come from the same combination, but have a greater density of melanin in the outermost layer of the iris. Red and purple eyes, which are much rarer, are due to almost no pigment. In fact, red eyes have no melanin at all. So all we see is the reflection of blood vessels. When there is some pigment, but the amount is so small that wavelengths cannot be emitted; The red and blue colors interact with each other to form the rare purple color.
Source: https://popsci.com.tr/ Photo: https://tr.10steps.org/