Now, half of all people in the U. Worldwide, that number could be even greater. The brown color comes from melanin, a pigment in our eyes that also gives a brown color to hair, skin and other cells. The iris is made up of two layers of muscle and other kinds of cells. In most people, the back layer has at least some brown pigment in it, even if their eyes don't look brown. The more melanin there is in the iris, the darker brown it will be. Scientists trace the historic change back to a single common ancestor. That person had a change in a gene that controls melanin production. This change, or mutation, is believed to have reduced the production of melanin in the iris. Some eyes appear blue, green or hazel not because they have different color pigments, but because they have less melanin.
Zafira. Age: 32. The ultimate adult XXX star usually available only for traveling meetings. Services: Sex In Different Positions, Oral, Oral With Condom, Kissing, Kissing With Tounge, Cum On Body, Deep French Kiss, 69 Position, Extra Ball, Erotic Massage, Striptease, Couples, Light S/M, Toys.
Brown eyes are overwhelmingly the most common
Benefits of brown eyes
Posted on August 25, in General Eye Care. When someone wants to enhance their vision, they may try contact lenses or seek out LASIK eye surgery. But what if they want to change the color of their eyes? People have long been fascinated with eye color; after all, eyes come in a wide range of shades. Exactly what color are your eyes? Blue with brown spots? Green with gray spots? The genetics of eye color is very complicated.
What causes brown eyes?
Throughout the world, 79 percent of people have brown eyes and 5 percent have hazel eyes. These two colors are often considered the same color, but they are two distinct hues. The iris of your eye is the part that has color. There are genes that work to determine whether your eyes are brown, hazel, or another color. Learn More. Both brown and hazel eyes are in the brown family. But hazel eyes feature other colors in addition to brown. Pigmentation plays a major role in whether you have brown or hazel eyes.
Eye color is a polygenic phenotypic character determined by two distinct factors: the pigmentation of the eye 's iris   and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of melanin in the iris pigment epithelium located on the back of the iris , the melanin content within the iris stroma located at the front of the iris , and the cellular density of the stroma. The brightly colored eyes of many bird species result from the presence of other pigments, such as pteridines , purines , and carotenoids. The genetics and inheritance of eye color in humans is complicated. So far, as many as 15 genes have been associated with eye color inheritance.