When the baby's eye color begins to change - color determination table

April 14, 2021

We do not choose our height, build, shape of ears and nose, eye color - every person inherits all this from their parents, and often from their ancestors. One family is characterized by tall growth, another by red hair. As for eye color, its inheritance is not considered a strictly transmitted trait. But established patterns are still present. Let's tell you more about them.

More than seven billion people live on our planet and each of them has a set of individual traits. Eye color is considered a feature that, in most cases, remains unchanged throughout life. But at the same time, there is an opinion that in older people the color loses its brightness.

From generation to generation?

A person inherits eye color from his parents through a recessive-dominant trait. In simple words, one shade can suppress another. Brown is considered dominant. Often it is this that suppresses light eye shades, which are recessive. But there are exceptions here too. If you had ancestors with light shades of eyes, then the chance that a brown-eyed and light-eyed couple will have a light-eyed child increases. Let us visually consider cases of one or another manifestation of eye color in a child.

What factors cause the change in color of the iris

According to the laws of genetics, a dark shade is always dominant, and a light shade is recessive. Therefore, if one parent has brown or black eyes, the child should, in theory, inherit that color. But in reality, genes are often “triggered” that provide the iris with a blue, gray, blue or green color, passed on to the baby after 2-3 generations.

A particularly striking contrast between appearance and eye color can result if parents belong to different races and nationalities. There are some interesting statistics regarding this:

• Most representatives of the Caucasian race (this includes Slavic peoples) have light eyes - blue, blue, gray, gray-green, hazel;
• those who belong to the Negroid and Mongoloid races, the indigenous inhabitants of the Near and Middle East, have eyes almost always brown or black;
• an inexplicable phenomenon - in Turkey, almost 20% of local residents have green eyes. Olive, swamp, green-gray, or green-brown irises are common;
• Brown-eyed people are a minority in the Scandinavian countries, Iceland, and the Netherlands. But blue and blue eyes are common there. In Iceland, 40% of the population has a green iris.

What is the rarest eye color in the world can be found in our article at the link.

Eye color is determined in the embryo – at the genetic level. The ability of cells to produce melanin is also determined there. The more actively they are able to “work” on its synthesis, the darker it ultimately turns out.

However, melanin synthesis is possible only in light. It requires exposure to ultraviolet rays on the organs of vision. In the womb, the baby has no chance of “contacting” the sun. Therefore, the eyes of newborns are most often of an indefinitely faded color.

Another significant factor is the “density” of the iris tissue. If collagen and elastin fibers form a fine-mesh “mesh”, intertwining closely, the tissues are saturated with pigment to the maximum. As a result, the iris becomes brown or black. When the “mesh” is loose, the child will have blue, gray or green eyes.

The child inherits the shade of the iris from his parents, less often from distant relatives

In addition to the “desire” of the iris to acquire a shade inherent at the genetic level, the eyes of infants are capable of changing tone and situationally. Attentive parents notice that it darkens if the baby is tired, irritated or hungry. Slightly cloudy when he wants to sleep. Bright shining eyes are a sign that the child is calm and happy with everything.

Inheritance of eye color: interesting facts

The eye is rightfully considered the most important of the sense organs. It is thanks to vision that a person receives 90% of information from the world around him. This is a kind of complex optical device, the main task of which is to transmit an image through the optic nerve to the brain for the purpose of its subsequent processing. The inheritance of iris color is fraught with many interesting myths and true theories. Let's look at the most popular of them.

It turns out that people with brown eyes have cells with a blue tint hidden under a thin layer of brown pigmentation.

It is believed that dark-eyed people are trusted more than light-eyed ones.

In severe frost, as well as in artificial bright light, light-eyed animals can change their eye color.

There is an opinion that pirates wore a patch over one eye so that one of them would get used to the light and the other to the dark. This was necessary to see what was happening both on deck and below it.

Only 1% of people on the planet have a different color in the iris of both eyes.

You've heard the theory more than once that carrots are good for vision. Yes, vitamin A, which is contained in this vegetable, is important for health. However, there is no evidence that eating carrots affects the quality of vision. Where does this belief come from? During World War II, the British invented a new radar that helped identify German bombers at night. So, to hide this, the British Air Force came up with and spread the theory in the press that night vision is caused by the carrot diet of pilots.

Child's eye color. Genetic opportunity in %

My friends know how much I am interested in the question of the color of my son's eyes.

For those who don’t know, I’ll tell you: Our dad has brown eyes. My eyes are green with pronounced heterochromia (there are brown veins in the eyes, the rim of the eyes is gray, the iris is green. That is, the eyes are three-colored).

I always thought that in a couple like ours, the child would be 100% brown-eyed, but almost a year has passed, and my son’s eyes are sky blue))) And having begun to study this issue in more detail, I came across the article described below. Everything is quite clear) So I hasten to share with mommies)

Eye color: from grandparents to our grandchildren: how it is transmitted genetically. Tables for calculating the eye color of an unborn child.

During pregnancy, many parents are eager to find out what eye color their unborn child will have. All answers and tables for calculating eye color are in this article.

Good news for those who want to pass on their exact eye color to their descendants: it is possible.

Recent research in the field of genetics has discovered new data on the genes that are responsible for eye color (previously 2 genes were known that were responsible for eye color, now there are 6). At the same time, today genetics does not have answers to all questions regarding eye color. However, there is a general theory that, even with the latest research, provides a genetic basis for eye color. Let's consider it.

So: every person has at least 2 genes that determine eye color: the HERC2 gene, which is located on human chromosome 15, and the gey gene (also called EYCL 1), which is located on chromosome 19.

Let's look at HERC2 first: humans have two copies of this gene, one from their mother and one from their father. HERC2 can be brown and blue, that is, one person has either 2 brown HERC2 or 2 blue HERC2 or one brown HERC2 and one blue HERC2:

HERC2 gene: 2 copies* Human eye color Brown and Brown brown Brown and blue brown Blue and blue blue or green

(*In all tables in this article, the dominant gene is written with a capital letter, and the recessive gene is written with a small letter, eye color is written with a small letter).

Where does the owner of two blue HERC2 green eyes come from - is explained below. In the meantime, some data from the general theory of genetics: brown HERC2 is dominant, and blue is recessive, so a carrier of one brown and one blue HERC2 will have brown eye color. However, a carrier of one brown and one blue HERC2 can pass on both brown and blue HERC2 to their children with a 50x50 probability, that is, the dominance of brown does not in any way affect the transmission of a copy of HERC2 to children.

For example, a wife has brown eyes, even if they are “hopelessly” brown: that is, she has 2 copies of brown HERC2: all children born with such a woman will be brown-eyed, even if the man has blue or green eyes, so how she will pass on one of her two brown genes to her children. But grandchildren can have eyes of any color:

HERC2 from the mother is brown (in the mother, for example, both HERC2 are brown)

HERC2 from father - blue (father, for example, has both HERC2 blue)

HERC2 in a child is one brown and one blue. The eye color of such a child is always brown; at the same time, he can pass on his blue HERC2 to his children (who can also receive blue HERC2 from the second parent and then have eyes either blue or green).

Now let's move on to the gey gene: it can be green and blue (blue, gray), and each person also has two copies: a person receives one copy from his mother, the second from his father. Green gey is a dominant gene, blue gey is recessive. A person thus has either 2 blue gey genes or 2 green gey genes, or one blue and one green gey gene. At the same time, this affects the color of his eyes only if he has blue HERC2 from both parents (if he received brown HERC2 from at least one of his parents, his eyes will always be brown).

So, if a person received blue HERC2 from both parents, depending on the gey gene, his eyes may be the following colors:

gay gene: 2 copies

Human eye color

Green and Green

Green and blue

blue and blue

General table for calculating the color of a child's eyes, brown eye color is indicated by “K”, green eye color is indicated by “Z” and blue eye color is indicated by “G”:

Eye color inheritance table

Heterochromia: visible uniqueness

The meaning of the word “heterochromia” has Greek roots; it is literally translated as “different color”. Interestingly, this uniqueness is most often found in women; there is no scientific explanation for this fact.

A child's eye color develops over the first two years of his life. That is, the original color can change several times. This regulates the pigment melanin. The color of the iris will depend on how this pigment is distributed. If there is a lot of melanin, then the eyes will be dark in color; otherwise, a reduced amount of melanin will be reflected in light-colored eyes.

In the case of heterochromia, the mechanism of uniform distribution of melanin is disrupted.

If there is an excessive concentration of melanin in one iris, then this will contribute to multi-colored eyes, and if only in a certain area, then the pupil may even have two colors.

Until what age can a newborn's eye color change?

The process of darkening the iris begins from the moment the child first opens his eyes. If parents purposefully pay attention to this, they will notice even minor changes. External factors, such as natural or artificial feeding, sleep and wakefulness patterns, the presence or absence of diseases, are not able to speed up or slow down this process.

Most newborn babies have irises that are watery bluish, grayish, or dull greenish. Less common is bright blue. In the first case, it is difficult to “calculate” its final shade. Parents will be able to draw their first conclusions only after 2.5-3 months. By this age, the child is already meaningfully focusing his gaze on faces, toys, and interior items. The iris tone becomes more saturated and defined.

When the baby turns six months old, melanin synthesis is sharply activated. At this time, the iris can either darken sharply or remain almost unchanged.

In most infants, the original color of the iris changes to the one determined at the genetic level by 9-12 months. But sometimes the process lasts for 2.5-3 years. Rarely (1.5-2% of cases) the color becomes permanent only when the child is close to adolescence (10-12 years).

Parents should not immediately after the birth of a child wonder who his eyes look like. Most likely, this is not the final iris tone.

Indirectly, how long the process of changing the shade of the iris will take can be judged by taking into account the color of the skin and hair of the newborn. In initially dark-skinned and dark-haired babies, the eyes, having “gained” pigment in extreme concentration and acquired a hazel, brown or black color, retain it for life. For fair-skinned and fair-haired children, the process takes longer. The color of their eyes changes 2-3 times.

Tax on Bashkir eyes

Did you know that in Bashkiria at the beginning of the 18th century a tax was introduced on appearance, or more precisely, on eye color? The author of this unique principle of taxation was Peter I. Thus, it was believed that the native Bashkir should have exclusively black eyes. And strangers and residents born as a result of assimilation had lighter eyes.

It turned out that black-eyed and brown-eyed people paid only two altyns, and those with gray, green, and blue eyes paid from 7 to 13 altyns. It was most difficult for albinos, for obvious reasons. The dark-eyed Bashkirs, although taxed at the lowest rate, soon rebelled and the contribution was abolished.

What eyes are typical for Bashkirs?

Epicanthus (the fold of the upper eyelid at the inner corner of the eye) is characteristic of approximately 20-25% of Bashkirs; this feature appears more often in women than in men. The eyes of the peoples of Bashkiria are predominantly dark, while a purely dark color can be seen in 30% of the inhabitants. There are also exceptions - people with light eyes and hair.

What could be the color of a newborn's eyes and how does it change?

The eyes of newborns only darken. If the tissues of the iris are initially saturated with melanin “to the limit,” then they will not become lighter.

What is the shade of the iris in newborns:

• blue. Typical if the baby is Caucasian. This faded shade can turn into almost any other darker color. It persists if the baby is diagnosed with albinism;
• blue. The iris tissue here is characterized by a high content of melanin. Often blue eyes, which have the property of reflecting light rays of the blue spectrum, are found among residents of northern countries;
• grey. The intensity of the shade is determined by the concentration of melanin, so it is difficult to find a baby with dark gray eyes. Light gray is essentially a variation of blue;
• brown. If a brown-eyed baby is born, then it can be argued that he inherited this shade from his parents. The tone can only become deeper, richer;
• black. An exceptional phenomenon if the baby does not belong to the Negroid or Mongoloid race;
• green. In order for the iris to acquire this rare shade, a pigment is needed that is “responsible” for the blue color, as well as lipofuscin, which gives its surface tissues a yellowish-brown tint. Congenital, rather than acquired, green color is rare. This tone appears gradually. Dark green eyes (olive, marsh) often turn into brown-green or brown over time;
• amber yellow. An even rarer shade. It turns out when there is only melanin and lipofuscin in the tissues, in the absence of blue pigment.

The final shade of a newborn’s iris does not appear overnight; the process of changing it lasts for at least a year.

Diseases affecting color

Sometimes eye color is affected not only by genetic factors, but also by the development of certain diseases. For example, hepatitis or jaundice is accompanied by yellowing of the white areas of the organs of vision, which can cause the iris to become darker. Often, even a common cold or illness in children is enough for the organs of vision to become less expressive and their color to become distorted.

Eye color can also change due to disease

Doctors recommend periodic iridology testing. This is a diagnostic event, the essence of which is to study the organs of vision and assess the condition of the iris using modern equipment. Many pathologies provoke a change in the patient’s gaze, as well as cloudiness. At the same time, clean and clear eyes can indicate the child’s good health.

Iridodiagnosis - diagnosis of diseases by modification of the shape, structure, color and mobility of the iris (from the Greek “iris” - “iris”)

There is another disease that affects eye color - albinism. Unlike the previously mentioned heterochromia, albinism is not harmless, because in addition to changing the patient’s appearance, the quality of visual functions also decreases. Albinos often experience phenomena such as eye hypersensitivity and impaired visual perception. The development of albinism is accompanied by discoloration of the iris of the eye, as a result of which it takes on a red tint. This is due to the presence of blood vessels.

Albino

If parents notice that their child’s eyes have acquired an unusual appearance or have changed in color, then they should seek advice from a specialist as soon as possible. Not all diseases that provoke such changes are safe for the patient’s body, so they should not be ignored, especially if we are talking about a small child. But, as practice shows, the development of serious pathologies or anomalies is determined immediately after birth, when an ophthalmologist conducts an examination in a maternity hospital.

How eye color is passed on from parents

Determining what eye color a child will have, taking into account only information about mom and dad, will be too rough a calculation. Although, if both parents are brown-eyed, they are more likely to have a child with the same brown eyes.

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It is not surprising that such a father and mother will give birth to a baby with gray or blue eyes. It is important to consider not only the color of each parent's grandparent's cornea, but also that human DNA carries at least 6 genes that can significantly influence eye color.

Mendel's first law

Gregor Mendel is a teacher of physics and biology who became interested in experiments on pea propagation. He was especially interested in the pattern of transmission of distinctive features of different varieties. He realized that each pea cell responsible for its color contains two genes. Each of the genes can carry information about either yellow color or green color. These color genes were called alleles. If a cell contained both genes carrying the yellow code, or both with the green color information, such cells were called homozygous. Mendel's first law states that if two parents whose cells are homozygous are crossed, then all individuals of the first generation of offspring will acquire the characteristics of the dominant gene.

If you try to apply this law to the inheritance of eye color, you should remember that you need to determine the color of the offspring not by two genes, like in peas, but by six. That is, each cell responsible for the color of the cornea carries six genes with color information. In order to unambiguously determine the eye color of a child from his parents, the table must contain possible options for crossing exclusively homozygous cells.

In other words, if for centuries the father’s family had only brown-eyed relatives, and the mother’s ancestors all had green eyes, then to determine the child’s eye color it is enough to know that brown is dominant over green, that is, the child will definitely be born brown-eyed. In real life, it is impossible to imagine a situation in which a person has homozygous cells responsible for eye color. Although the main rule of the predominance of dominant characteristics is fundamental.

Interesting. It often happens that a baby is born with an eye color like one of the grandmothers, and not at all like one of the parents.

From a genetic point of view

The color of the iris is influenced by certain genes (there are only 6 of them). Of these genes, several are dominant, that is, superior to others. Therefore, superiority will be achieved only by those external differences for which the dominant genes are responsible. There are other genes that are not as strong as the previous ones. Scientists call them recessive. The presence of weak genes, as a rule, does not appear on a person’s appearance.

Certain genes influence the color of the iris

Note! Scientists traditionally believe that the genes responsible for the light color of the iris are recessive, and those responsible for darker shades are dominant.

It would be wrong to believe that in a family of parents where both mom and dad have brown eyes, the child will be like them in everything. In fact, everything is much more complicated, because the child copies genes from both the father and the mother at the same time. Each pair copied consists of a recessive and a dominant gene, so the child may end up with different traits from their parents.

Interesting facts about eye color. Genetics in practice

An external characteristic may not be transmitted by genes immediately, but even after several generations, which is why not only parents, but also grandparents contribute to the formation of the color of the iris. The interaction of genes that are directly involved in the transmission of eye color occurs according to special patterns, thanks to which parents have the opportunity to predict the eye color of the future baby with the highest possible accuracy (more than 90%).

Eye color inheritance table