Principles of inheritance of eye color
Eye colour depends on pigmentation of the iris, which contains chromatophores with melanin. If a lot of pigment, the eyes turn out brown or brown, and blue-eyed people disrupted production of melanin. For a bright eye color responsible mutation, which occurred not so long ago – about seven thousand years ago. Gradually it spread, but the mutated gene is recessive, so brown-eyed people are much more on the planet.
In its simplest form, the laws of inheritance can be described thus: in the formation of reproductive cells chromosome set of a human is divided into two halves. The cell takes only one second of the human genome, including single gene responsible for eye color. When two sex cells merge, and the embryo is formed, the genes meet each other in the area responsible for eye color are two of the gene. They will remain in the genome of a new person, but to the degree that external features can only one dominant, which suppresses the effect of other, recessive gene.
If there are two dominant, for example, responsible for brown eye colour, the child's eyes are hazel, if two recessive light.
Blue-eyed child of brown eyed parents
From brown-eyed parents can be born a blue-eyed child, if both have the genome recessive genes for light shade of eyes. In part of the gametes in this case, it gets dominant, which is manifested in the form of brown eyes, and the other part is a recessive gene. If at conception will occur between cells with the genes for light eyes, child of light eyes.
The probability of this happening is around 25%.
Much rarer situation, when a blue-eyed parent brown-eyed children are born. From the point of view of simplified laws of genetics described above, it is impossible to explain: how could take the dominant gene in the baby, if the parents he had not appeared, so they don't have it? And yet there are such cases, and genetics easily explain it.
In fact, the principles of transmission of characteristics by inheritance is much more complicated than it seems. In humans, eye colour is a responsibility, not one pair of genes, and a set, which mixed the genes inherited from many previous generations. The combination can be very diverse, so you can never predict 100% what eyes will the child. Even scientists still don't fully understand the schemes of inheritance: eye color may affect a variety of genes in different chromosomal regions.
Advice 2 : Eye color future baby: truth and myths
Almost all people ever heard the common myth that the color of the eyes of all newborns is sky blue. In fact, it is not so. At this age all kids the color of the eyes really almost the same, but it can be grayish, dull blue or bright blue. The amount of melanin pigment in infants is small, it increases during the first year of life and that the intensity of production affects the final color of the eyes of a child.
This process for all children ends at the time, but in most cases by a year, you can define a constant color. However a change of subtle shades in some cases lasts up to 3-4 years.
What affects the intensity of melanin production? Mainly from heredity. But don't think it's too simple - the child's eye color will not necessarily be the same as one parent or a mixture of their colors. On this subject it is useful to enlighten jealous and full of prejudices of the spouse, in order to avoid misunderstandings.
So, the child's eye color may differ from color of eyes mother and father. But some guesses based on the parent traits you can offer.
If both parents are brown-eyed - child will be the same in 75% of cases. It is also possible to green (20%) and blue (5%) eye color.
If one parent is brown-eyed and the other green-eyed, half of the cases the child will inherit brown eyes, 40% green and 10% blue.
Brown-eyed and blue-eyed parents 50% will get a brown-eyed child, the rest 50% will be blue eyed, but green eyes in this situation is not likely to succeed.
Green-eyed parents give birth to the same child in 75% of cases, in a quarter of cases the eyes of the offspring will be blue, and in the unlikely event (<1%) to be born a brown-eyed child.
Union blue and green eyes are unlikely to give brown eyed offspring, and their colors are distributed with equal probability (50%).
And finally, two blue-eyed parents with a 99% chance you will get the same child. In 1% of cases, they the baby will be born with green eyes and brown eyes have a child of such a pair is unlikely to emerge.
There are some cases when this rule may not apply. Sometimes there are people with an unusual appearance - they have different colored eyes. Though gone are the days when they were considered witches, supporters of the devil, and strongly eschewed, such a feature appearance still surprises and attracts attention. However, no damage appeal it causes.
The baby can be born accurate your copy, or Vice versa, would not you like, he may be the eyes of your husband, the curls your mother's freckles or your father. How important is that? Probably more important to make every effort to have your child grow up happy and decent man is a legacy and will be your main gift to him.