What determines the color of the eyes?

How do children inherit the color of the eyes? Can you predict what it will be like in a child? Why are they albino pink? If both parents have brown eyes, can they have a blue-eyed baby? How is the color of the iris formed? These issues are relevant at all times. The answer to them is contained in a combination of internal and external signs of the body, formed on the basis of the genotype, as well as acquired as a result of individual development. What does this mean and what determines the color of the human eye?

This characteristic is determined by the pigmentation of the iris (iris), consisting of the ectoderm (posterior) and mesodermal (anterior) layers. That is, the color of the human eye depends on the nature of the distribution of fuscin (it promotes the production of a visual pigment, absorbs light and prevents its dispersion and reflection, resulting in improved clarity of visual perception of the image) in pigment cells of the back layer and melanin (natural dark matter) in pigment-containing and reflective Cells (chromatophores) of the anterior layer. The color is also affected by the state of the vessels and fibers of the iris, the different number and nature of the pigment, which, in turn, determines genetics. Eye color is caused by genes. But not all of them have been studied.

Melanin is a colored substance, it affects not only the color of the eyes, but also the hair and the shades of the skin. Yet, what determines the color of the eyes? The more melanin is contained in the mesodermal layer, the darker the iris, and the less it is distributed in the pigment cells of the anterior layer of the iris, the lighter it will be. There are melanin brown and black (or eumelanin), and also yellow (or pheomelanin). For the nature and quantity of this natural substance and its distribution, certain genes are responsible. As a result, the color of the iris can be blue, blue, gray, green, amber, marsh, black or brown. The child will inherit similarity with a parent with dominant characters (brown, light brown and green) and he will not get the color of the parent's eyes with recessive signs (blue or gray).

In blue eyes, the back layer is colored blue due to the vessels formed by collagen fibers, the front layer is characterized by a minimum content of melanin. Blue differs from blue with a greater density of whitish fibers: the higher their density, the lighter the iris. The gray color of eyes is explained by an even greater density of collagen. In the front layer of green there is a small amount of melanin, because of the blue color of the back layer, the iris is heterogeneously green and of different shades. What determines the color of the eyes of the amber? Pigment lipofuscin ensures their uniform coloration. With a moderate content of melanin in the outer shell, the eyes become marshy or nutty. Hives occur when in chromatophores contains a lot of melanin. Black is characterized by a high content of this pigment, which completely absorbs light. In albino it is absent, and the iris appears pink or red due to the reflection of the color of the blood vessels.

Newborns have a blue iris, but it can darken over the next few years. How is this explained and what determines the color of the child's eyes? Melanin in the body at the time of birth of the fetus is not produced, since it was not required until this time protection from ultraviolet rays, which is performed by a dark pigment. Its main purpose is to prevent radiation damage to body tissues. After birth, the production of melanin by specialized cells (melanocytes) begins. Therefore, the true color of the child's eyes can be determined no earlier than three years, although changes sometimes occur up to 10-12 years. In adults, iris color may also change due to medication or health problems. For example, yellowish color appears due to the accumulation of lipofuscin.

Usually the brown eyes are considered dominant, and the blue ones are recessive. But modern science has proved that everything is not so simple. The darker the color, the more it dominates: brown over green, green above blue. But not always the child will be brown-eyed, if the iris at mum and the daddy brown. In children, it can be different. This is usually caused by a malfunctioning development of pigment transport, local trauma, or in the womb, or soon after birth, as well as a genetic disease.