What color of eyes will the child have?
As soon as the kid comes into this world, grandparents, friends and acquaintances, aunts and uncles and, of course, the newly-made parents themselves are wondering about who the crumb looks like. Whose nose, mouth, cheeks. And one of the main questions is: "What color of eyes will the child have?" Can a blue-eyed parent have a brown-eyed girl? Or a dark-eyed couple - a boy with blue eyes? Let's understand!
What determines the color of the eyes in children? There can be no unequivocal answer, after all, although genetics decides 90%, the remaining 10% still depend on the case.
The color of human eyes is determined by the amount of pigment called "melanin" in the iris of the eye. The minimum amount of melanin means the color of the eyes is blue, the maximum number is brown. The remaining colors and shades are between these two points of the spectrum. The amount of pigment is determined genetically.
All newborn babies have either a dark brown color or a gray-blue eye color. Then, depending on the speed and amount of melanin produced by the body, the eye color will change. Finally, it is possible to determine what color of eyes the child will have after reaching three years. Up to this age, it can vary, but in most children everything is clear already at the age of six months to a year. There are exceptions to the rules: there are people whose eye color changes throughout life.
The error is the assertion that if both parents are brown-eyed, the child should also have this eye color. To their surprise, a blue-eyed child can also be born. How many families broke up because of such cases when people had no idea what genetics is. Of course, suspicion fell on a woman. And yet everything is quite simple. Let's look at the simplest example of a modern school textbook on biology.
What color will the child have? You can not guess in advance. Each person has two variants of the same gene: maternal and paternal. Two versions of the gene are called alleles. One of them will be dominant, the other - recessive. So, the brown eye color is dominant. But a child can also receive a recessive allele from one of the parents.
Let's designate the color of the eyes with the letter "K", and the blue color, which is recessive, a small "g". For the color of the eyes in the human body is responsible for the combination of two alleles - one from each parent. Thus, the brown-eyed man will have either a combination of "KK" or "Kg". A blue-eyed child, in turn, can only have "gg".
A child can have blue eyes, if both dark-eyed parents have incomplete dominance of brown color, that is, both have the algon "Kg". In other words, if the grandmother or grandfather of the child has blue eyes, their grandson may well be blue-eyed!
Mom "Kr" + dad "Kr" = KK (brown-eyed baby) or Kg (brown-eyed child) or gg (blue-eyed).
Today, there are even some kind of calculators to determine what color the eyes of a child will have. Of course, our explanation is very schematic and does not reflect the complexity of genetic processes. Still, the conception and development of a child is a great mystery, and our minds are not always able to realize it. What color will the child have? Is it important? It is much more important that he be healthy and live a happy life, is not it?