Blue-eyed baby with brown-eyed parents: is it possible?

Eye color is a unique feature that accompanies a person throughout his life. It is determined genetically and depends on many factors. Young spouses always want to know how to determine the eye color of their unborn child, and whether this is possible at the present stage of scientific development. The answer is positive - genetics and statistics help to tell what shade of iris your son or daughter will inherit from you.

Eye color is determined by the amount of melanin pigment in the outer layer of the iris. In addition to the concentration of melanin, the number and thickness of connective tissue fibers in the same layer of the iris plays a role.

What colors do people have eyes?

Blue – there is little melanin, the fibers of the intercellular substance are thin;
Gray – there is little melanin, but the connective tissue fibers are denser;
Green - more melanin than blue-eyed, the quantity and quality of fibers may vary;
Brown - the concentration of melanin is even greater, the characteristics of the fibers may vary.

There are two extreme options

Red – complete absence of melanin, the shade is determined by the color of the blood flowing through the vessels (with albinism, the hair will also be white);
Black – the maximum amount of pigment.

Parents often ask the question: “What is the most common eye color on the globe?” Researchers have found that the majority of the world's inhabitants are brown-eyed.

Dark eyes are typical for residents of warm regions and are more common among representatives of the Negroid and Mongoloid races. Light shades of the iris arose later in the process of evolution, when the ancestors of people began to settle in the northern territories of our planet.

The color of the iris can change throughout life under the influence of age, weather conditions, exposure to physical factors and certain diseases. The shade of the eyes is also influenced by a person's mood, his general emotional state and how many hours he sleeps. When we are happy or in love, the color of our eyes appears brighter to others.

Modern data suggest that a trait such as eye color is encoded by two genes located on chromosomes 15 and 19 - HERC2 and EYCL1. Each of them can be presented in two variants (alleles) - dominant and recessive. Every person has two copies of each gene, received from their mother and father.

Mother's eye color
Father's eye color	Children	Brown	Green	Blue	Grey
	Brown	Brown eyes	Brown-eyed	Brown eyes	Brown eyes
			Blue eyes	Blue eyes	Grey-eyed
			Green-eyed	Green-eyed	Green-eyed
	Green	Brown-eyed	Green-eyed	Blue eyes	Green-eyed
		Green-eyed	Blue eyes	Green-eyed	Grey-eyed
		Blue eyes
	Blue	Brown eyes	Green-eyed	Blue eyes	Blue eyes
		Green-eyed	Blue eyes		Grey-eyed
		Blue eyes
	Grey	Brown-eyed	Grey,	Blue eyes	Grey-eyed
		Green-eyed	Green-eyed	Grey-eyed
		Grey-eyed

If mom has brown hair and dad has blue

Let's consider the option when mom has brown eyes and dad has blue eyes. Such parents may give birth to children with brown eyes, or less often, the color of the child’s eyes will be green or blue.

If mom has blue ones and dad has brown ones

It happens that the mother has blue eyes, and the father has brown eyes. For such spouses, the situation is similar to that described above (the child will have the same options for eye shade).

If mom is green and dad is brown

It happens that the mother has a green iris, and the father has a brown one. Their sons and daughters may have brown, green or rarely blue eyes.

If mom has brown, and dad has gray

Genetics indicate that if a woman is the owner of brown eyes, and her beloved has gray eyes, then their descendants will inherit a brown or gray tint of the iris.

If mom's are green, and dad's are blue

A green-eyed woman and a man with blue eyes are likely to give birth to children who will have green or blue eyes. Such parents cannot produce babies with dark eyes.

If mom has blue ones and dad has green ones

Medical consultants explain that if a spouse has green eyes and his life partner has a blue iris, then they will have the same children as their previous parents.

If mom has brown, and dad has green

Remember that a brown-eyed mother and a green-eyed father will give birth to babies with brown eyes, green or blue.

If mom's are gray, and dad's are green

What color will the babies' eyes be when the expectant mother has gray eyes and the father has green eyes? They should expect green-eyed or gray-eyed offspring.

What eye color will the child have?

Features of two-tone eyes

The frequency of heterochromia is approximately 10 cases per thousand. Its main reason is the excessively high or low content of coloring pigment. This substance is called melanin and is responsible for one or another shade of a person’s eyes.

The color of the iris consists of several pigments: yellow, blue and brown. The shade of the eyes is determined by the proportion of these pigments. An interesting fact is that each individual has his own form of heterochromia, i.e. it is impossible to meet a person with identical manifestations of the anomaly. This is not a disease, but a unique feature of a person.

There are several types of heterochromia:

Complete heterochromia is manifested by the fact that both eyes have a different shade. Most often there are people with various combinations of blue; one eye may also be brown, the other blue;
Sector or partial - the iris is painted in several contrasting colors. The most common combinations are gray, blue and brown. Sometimes blue eyes with white splashes are found. In most cases, this form of anomaly is caused by mechanical damage to the visual apparatus or a previous disease;
Central - the color of the iris differs in that several clearly defined multi-colored rings are visible on it.

There is no need to treat heterochromia, since the anomaly does not affect the quality of visual function in any way. Only in rare cases, different eye colors are a symptom of ophthalmological pathology.

Odds or percentage of probability

Mom and dad have brown eyes, three quarters of all children born will have the same shade of eyes. The likelihood that they will have a green-eyed or blue-eyed baby is much lower - 18.75% and 6.25%, respectively.

When the first parent has brown eyes, and the second has green eyes, then in half the cases such spouses can give birth to a brown-eyed baby. In 37.5% of cases, their son or daughter will have a green iris, and only 12.5% of the heirs will have blue eyes.

Heterochromia

Heterochromia is a rare natural phenomenon, which refers to the presence of different eye colors in one person, caused by heterogeneous synthesis of the melanin pigment. Heterochromia can occur both within one iris and in each eye separately.

In Medieval Europe, many people with different eye colors were considered connected with the other world. Nowadays, some politicians, actors and singers have this feature (Tim McIlroth, Alice Eve, etc.). Modern medicine has established that this condition most often does not pose a danger to the child’s life.

But parents need to be careful and, in case of any vision problems, show the baby with different eyes to an ophthalmologist, since heterochromia can be a companion to certain diseases (a genetic test may need to be performed).

If heterochromia appears in an adult, this is always evidence of a pathological process (inflammation, tumor, metabolic disorder or injury) that develops in some part of the body.

How to determine eye color in newborns?

All people are born with blue or blue eyes. At what age can you see the real shade of a baby’s iris, and at how many months does a child’s eye shade change? Only after six months to a year of life on Earth does the child begin to develop the final color of the iris, which will remain for the rest of his life.

Permanent coloring of the iris is formed before 2-4 years of age. In addition, teenagers can expect surprises during puberty, when changes in hormonal balance begin and sometimes eye color changes again.

The unique shade of the eyes is a miracle given to us by nature. Thanks to genetics, today future parents can not only imagine what eye color their future child will have, but also give birth to a beautiful, healthy baby.

Character by eye color

Already during pregnancy, a woman wants to learn from her parents how genetics influence the child’s eye color. The probability is calculated in advance. 90% of this depends on genetic predisposition. With a small amount of melanin, the color will be blue. The high content of coloring pigment makes the child's eyes brown. In other cases, the shades will be distributed between the layers.

Heterochromia of the eyes. Causes and myths

Heterochromia is a physiological deviation associated with the fact that a person’s eyes have different colors. This phenomenon is not universal, but quite frequent. On average, five people out of a thousand have different eye colors. Similar deviations occur in animals.

Eye color is directly determined by the amount of melanin contained in the iris. For example, the lower the amount of melanin, the lighter the eyes and vice versa. Brown-eyed people have a lot of this substance in their iris.

Under normal conditions, melanin is distributed evenly between the organs of vision, but there are situations, various kinds of failures, in which the distribution occurs unevenly, as a result of which the iris in each eye acquires its own shade.

In ancient times, people shunned, or, on the contrary, worshiped those with heterochromia, considering them sorcerers or messengers of higher powers. During the Inquisition, owners of such a defect were subjected to torture, as were women who gave birth to children with such a pathology. Such women were accused of having connections with the devil.

The medical rationale for heterochromia is much more prosaic. And today, such a feature becomes pride for some, while others, on the contrary, are embarrassed by such a defect and try to correct it. At the same time, there are various myths associated with the appearance of such a defect.

Causes of heterochromia of the eyes

And so, the reason for this phenomenon is the uneven distribution of melanin between the eyes, but the reasons for this effect can be different.

Hereditary manifestation is quite common. If one of the parents has heterochromia, then the probability that the child will inherit this feature is close to 100%. It is not uncommon for this pathology to manifest itself after a generation. However, a congenital anomaly is far from the only option.

A different shade of the cornea in the eyes can occur as a result of injury to the eye by a foreign object. For example, if the eye is injured by metal shavings and if this particle is not removed in a timely manner, the blue iris may acquire a brown or green tint. An acquired pathology of this kind is called metallosis in medicine.

Fuchs syndrome or uevitis. This disease occurs due to inflammatory processes occurring in the choroid of the eye. As a result, clouding of the eye occurs and visual acuity decreases.

Gradually, the color of the iris, but in fact, just clouding, intensifies. The lesion is most often unilateral, but it can also be bilateral.

In fact, it would be a stretch to call this phenomenon heterochromia, since what occurs here is not a change in the color of the iris, but clouding.

It is important to remember that a person’s final eye color is formed by the age of two years. Therefore, it is important that parents monitor the child, and if the effect of different eye colors is noticed, it is necessary to contact an ophthalmologist.

Types of heterochromia eyes

Heterochromia is divided into three types:

– complete, when the eyes are completely different in color from each other;

– partial, when the iris is colored unevenly, in fragments. Sometimes the effect appears in the form of random spots, sometimes the iris appears to be divided in half;

– central, when the color change is observed only near the pupil.

Does heterochromia affect the patient's well-being?

Heterochromia itself does not affect the condition and well-being, but it is worth understanding that its manifestation is not always the effect of a genetic predisposition. Differences in eye color can be a signal of serious diseases, such as:

– Waardenburg syndrome, which in advanced cases can lead to the appearance of gray strands at a young age and hearing loss;

– neurofibromotosis, expressed in the threat of developing bone abnormalities. This disease begins with a change in pigmentation, which later develops into a tumor-like formation.

The ophthalmologist will determine the nature of the color change in the iris and, in case of danger, refer the patient for additional examination.

Myths accompanying heterochromia

This deviation is constantly accompanied by various myths. And if in ancient times it all boiled down to the fact that eyes are different colors, this is something otherworldly, but today the creators of myths compete in the sophistication of information noise, balancing on the brink of facts.

People with heterochromia are colorblind

It is a myth. Color blindness is not a result of the amount of melamine in the iris. People with this pathology distinguish colors in the same way as people with “normal” eyes.

Different eye colors lead to different vision in the eyes

This is also a myth. The optical power of the eye does not depend on the color of the iris. Patients with heterochromia can have either excellent or poor vision, both in pairs and in each eye separately. It all depends on various factors.

All owners of heterochromia are nervous and unsociable

There is some truth here. Some children who have eyes of different colors begin to withdraw into themselves during their school years due to ridicule or excessive attention from peers.

This becomes the cause of psychological instability. However, a lot depends on the parents.

If you explain to a child and convince him that there is nothing special about eyes of different colors, he will be easier to handle excessive attention to himself.

People with heterochromia are more susceptible to eye diseases and diseases in general

This is also a myth. There is no officially recorded evidence that this deviation affects the immune system and somehow contributes to the development of diseases. And all stories in this regard are most likely based on the fact that a change in the color of the iris can be a signal of a developing disease. For example, Waardenburg syndrome or neurofibromotosis.

How to get rid of heterochromia?

Many people wonder whether it is possible to get rid of such a deviation and how to make both eyes have the same iris color. Ophthalmologists believe that if there are no symptoms of a dangerous disease, intervention in the form of surgical and drug treatment is not required. On the contrary, it is even dangerous.

Unfortunately, in some cases, heterochromia, when it is partial, is expressed in a very ugly way. In these cases, therapeutic treatment or surgery is used. Unfortunately, changes are not always successful.

The least dangerous option is changing eye color using contact lenses. Both simple color ones, without diopters, and correction ones are suitable here. The choice of such products is very large, the main thing is to choose the right option and follow the rules for wearing CL.

Possible options

Eye color varies depending on the density of the fibers and the distribution of pigment. The brain transmits information to the optic nerves. They are part of the iris. Melanin acts as protection against ultraviolet radiation. The pigment is formed from cholesterol and tyrosine. More than 80% of children are born with light eyes; after 3–4 years, a change occurs. At this stage, the shade will remain for life. Sometimes the period lasts up to 10 years.

What eye color are babies born with?

karim;
blue;
green.

Sometimes the shade changes after six months under the influence of genetic factors and the sun. There are four colors of the pupil: gray, green, blue and brown. As a rule, children with brown eyes remain the same color throughout their lives. Large production of melanin leads to the fact that the iris becomes dark.

A dominant and recessive gene from both parents causes the eye color to be different at birth. Most children are born with a blue tint, less often with a gray tint. These shades fade to gray, turn into green or, conversely, into brown.

Eye color chart for parents and children:

Despite various hypotheses, Mendel's law turned out to be the most convincing. It says that color is determined by a dominant dark gene. It surpasses the individual characteristics of light genotypes.

Six-month-old babies, depending on their mood, change eye color. Already inside the mother, the pigmentation of the iris is laid down. When it is born, the iris takes on its own color. Parents pass on color by inheritance. Melanin formation is important. In small quantities the iris is light.

Influence of genes

Research has helped identify patterns and identify exceptions to the rules to predict what eye color a child's parents will have. This is an opportunity to draw conclusions about shades with a high degree of probability. Many families confirm the correctness of the hypotheses.

Basic patterns:

Parents with dark eyes have children born with the same color;
if mom and dad are light-colored, then the newborn’s vision organs will be blue or gray;
in case of a large difference in shades, the dark color dominates.

Such characteristics helped to form an almost 100% ratio of the characteristics of relatives. We found out that the probability of a blue-eyed mother and father with a green tint will be 60:40 in favor of a dominant light color. The tone and inclusions of the iris are passed on through generations from grandparents.

Factors influencing eye shade:

the number of outer and inner layers of the iris;
fiber density;
heat or cold.

Other genes also influence shade. Blonde people with light skin do not have dark eyes. If a person is of Negroid race or has tanned skin, the baby will be brown. A gene on chromosome 15 is responsible for coloring blue and brown, green and blue - on chromosome 19.

Chances

Eye color is inherited from parents. Two genes are responsible, which are passed on to HERC2 at the time of conception. At birth, a person can have two genes - brown or blue, as well as one chromosome for each color. The EYCL1 gene carries green and blue shades, in this case green is dominant.

Does eye color change after birth?

Yes, for the first four years. However, there have been cases where a boy entered school with blue eyes and graduated with green ones. The organs of vision may be different, differ in the multi-colored shell of the iris. This case is called heterochromia. This is an individual natural process that indicates a disease. To clarify, you will need to consult a doctor.

If the parents have green and blue eyes, then there is a 25% chance that the child’s eyes will be light green, blue with a small yellow halo around the pupil, dark with a blue tint, bright swamp.

Blue and brown colors give a 40% chance of a completely light or brown shade, as well as gray with yellow splashes and clear shades of 10%.

Green and brown give a 50% mixed shade, 25% closer to green with a brown halo around the pupil. 12 and 11% each that the eyes will be blue with yellow and light brown with a blue edging. In children, the color changes after sleeping and waking up. This phenomenon is called a "chameleon". The eyes differ in a range of shades.

Blue is combined with white fibers, amber weaves in a reddish tint or golden if the lipofuscin pigment predominates. Green mixes with brown. When there is a lot of melanin, the organs of vision appear black. The high density of the outer layer blends with the gray color.

Statistics

The iris is necessary for protection from ultraviolet radiation. Over time, the color will change. Light colors will become faded due to fading of the pigment. The shell of brown eyes protects from blinding sunlight. Despite the data given, it is not always possible to predict the color. The influence of closely related relationships with different races and nationalities leads to the fact that blond children have green and brown eyesight, and babies with dark hair are born with a blue tint.

Statistics show that green-eyed people make up about 2% of the world. Most often they are born in Turkey and Iceland. Caucasians are distinguished by blue irises. Brown-eyed people make up more than 75% of the entire world population. A separate category is albinos, who have a red iris due to almost zero pigment.

Blue color is more common among northern peoples. They have a deep shade of indigo. Children are distinguished by emotionality and sensitivity. Babies with brown eyes have a cheerful disposition, frequent mood changes, are active, responsible and hardworking. Newborns with green pupils are purposeful, stubborn, persistent, and demanding.

Purple eyes are considered exceptional and attractive. They occur in the absence of melanin. Such kids always cause admiration.

Over time, the color can change from brown to blue. Light eyes are hidden under the dark pigment. Depending on its thickness, brown-eyed people have a different shade of the shell. Using laser surgery, the pigment is removed in 20 seconds, returning the blueness of the iris.

Many parents try to determine the color of their child’s eyes using a table. Despite the high coincidence rate, deviations occur. In addition to the usual color, the iris can be yellow or purple. Tone is not an important factor in shaping appearance. It is impossible to be completely sure of the shade. Parents look for similarities with themselves, and eyes are formed with the participation of chromosomes and genes of other relatives.

Many parents wonder what color their future baby's eyes will be. The answer will not be so simple. Certain genes passed on to the child from the parents are responsible for eye color. The issues of their inheritance, even by modern science, have not been studied well enough to say for sure what facial and character traits a child will inherit from his mother and father.

Top 8 interesting facts about eye color that you didn't know

From a school biology course, we know how the color of a child’s eyes is genetically determined, we know that brown color dominates over blue and it happens that a person has eyes of different colors.
We will tell you facts you didn't know. For example, at what age does eye color develop and why does our iris have one color or another? Fact 1: All people are born with light eyes

Please note that all newborn babies have blue-gray eyes. Ophthalmologists explain this very simply - babies have no pigment in the iris. There are exceptions only in the countries of East, Southeast and South Asia. There, children's irises are already saturated with pigment.

Fact 2: We acquire our final eye color in adolescence.

The color of the iris changes and forms by 3-6 months of a child’s life, when melanocytes accumulate in the iris. The final eye color in humans is established by the age of 10-12 years.

Fact 3: Brown eyes are blue eyes

Brown is the most common eye color on the planet. But ophthalmologists say that brown eyes are actually blue under the brown pigment. This is a consequence of a genetic mutation.

The outer layer of the iris contains a large amount of melanin, resulting in the absorption of both high- and low-frequency light.

Reflected light results in a brown (brown) color.

There is a laser procedure that can remove pigment and make your eyes blue. It is impossible to return the previous color after the procedure.

Fact 4: in ancient times everyone was brown-eyed

Researchers have found that 10 thousand years ago, all inhabitants of the planet had brown eyes.

Later, a genetic mutation appeared in the HERC2 gene, whose carriers decreased the production of melanin in the iris. This led to the appearance of the color blue for the first time.

This fact was established by a group of scientists at the University of Copenhagen led by Associate Professor Hans Eiberg in 2008.

Fact 5:
a little about heterochromia
This is what is called the different color of the iris of the right and left eyes or the unequal color of different parts of the iris of one eye.

This feature is explained by the fact of excess or deficiency of melanin due to diseases, injuries, and genetic mutations. With absolute heterochromia, a person has two different colors of the iris.

One eye may be blue, the other brown. There are 1% of people on the planet with such an unusual deviation.

Fact 6:
green is the rarest eye color.
1.6% of people on the planet have green eyes; it is the rarest, as it is eradicated in the family by the dominant brown gene. Green color is formed like this. The outer layer of the iris contains an unusual light brown or yellow pigment called lipofuscin.

In combination with the blue or cyan color resulting from scattering in the stroma, green is obtained. Pure green eye color is extremely rare: the color of the iris is usually uneven, and this leads to the appearance of numerous shades.

Most often, green eye color occurs in those whose genotype is dominated by the gene responsible for red hair color. Swiss and Israeli scientists came to these conclusions. These findings are indirectly confirmed by the high prevalence of green eyes among red-haired people.

The results of the study were published in the “Genetic Nature” section of the Nature.Com portal.

Fact 7

:
a little about other colors of the iris
Black color

the eye is similar in structure to brown. But the concentration of melanin in the iris is so high that the light falling on it is virtually completely absorbed. Black eye color is most common among members of the Mongoloid race in East, Southeast and South Asia. In these regions, the iris of newborn children is already saturated with melanin.

Blue color

The eye is the result of light scattering in the stroma (the main part of the cornea). The lower the density of the stroma, the richer the blue color.

Blue

eyes, in contrast to blue ones, are explained by the higher density of the stroma. The higher the fiber density, the lighter the color. As we all remember, this beautiful color scheme was partly the reason for the formation of fascist ideology. After all, according to scientists, 75% of the indigenous inhabitants of Germany have blue eyes. No other country in the world has such a concentration of blue-eyed people.

Walnut color

is a combination of brown (hazel), blue or light blue. And it can take on different shades depending on the lighting.

Grey colour

the eye is similar to blue, while the density of the fibers of the outer layer is higher. If the density is not so high, the eye color will be gray-blue. Gray eye color is most common among residents of Northern and Eastern Europe, in certain regions of North-West Africa, as well as among residents of Pakistan, Iran and Afghanistan.

Yellow

the eye is extremely rare. It is formed due to the content of lipofuscin pigment (lipochrome) in the vessels of the iris. But in most cases, the fact of this eye color is explained by the presence of kidney diseases.

Fact 8

:
Albinos can have both red and purple eyes
The most unusual and interesting eye color, red, is usually found in albinos. Due to the lack of melanin, the iris of albinos is transparent and appears red due to the blood vessels. In some cases, red, mixed with the blue color of the stroma, gives a violet eye color. However, such deviations occur in a very small percentage of people.

Prepared using materials: ailas.com.ua, medhome.info, glaza.by, medbooking.com, nature.сom, nfoniac.ru

Source: https://mag.103.by/novosti-kompanii/42553-top-8-interesnyh-faktov-o-cvete-glaz-o-kotoryh-vy-ne-znali/

Genetic predisposition

Parents are encouraged to find out what kind of eyes the child will have even before his birth, although this will be approximately. In biology classes, we all studied about genetics, which determines the formation of facial features or other properties of the unborn child, including eye color. Science has proven that eye color corresponds to 6 genes, and not 2, as was previously believed. But even today it is difficult for parents to predict what color your child will be - you can only guess.

The theory of genetic formation of a child’s eye color suggests the following variations:

There are 2 genes that have been well studied and by which the eye color of the unborn child can be determined. One of them is located on chromosome 15, and the other on chromosome 19. Both genes have 2 copies, one of which the child receives from the mother, and the second from the father.
The gene on chromosome 15 carries the colors brown and blue; there can be varieties: 2 brown, 2 blue or 1 brown and 1 blue. 2 brown genes carry brown eye color, brown and blue also carry brown color, but 2 blue genes can carry blue or green. Brown color is dominant. For example, a brown-eyed woman and a blue-eyed or green-eyed man will only have brown-eyed children, but their grandchildren will receive an unpredictable color.
The gene on chromosome 19 carries the colors green and blue. Cyan can also include shades of blue and gray. Green is dominant, blue is recessive. Blue eye color is caused by the highest gene on chromosome 15, so a person with two blue such genes may have different variations in the presence of gene 15. If he has at least 1 brown 15 gene, then his eyes, regardless of the 19 gene, will be brown. This is difficult, but this is genetics - with two green 19 genes the eye color will be green, with green and blue the result will be green again, and in the case of 2 blue genes it will be blue.

A simplified table is used to facilitate understanding.

What diseases can cause heterochromia of the eye shell?

“Different eyes” can be caused by both congenital and acquired diseases. Possible pathologies include:

Horner's syndrome is a consequence of damage to the sympathetic nervous system. In addition to changes in the color of the iris (most often the “owners” of the symptom are child patients), there is drooping of the eyelids, narrowing of the pupil, disruption of its normal reaction to light exposure, and sunken eyes;
neurofibromatosis type 1 is a hereditary disease that significantly increases a person’s risk of developing dangerous tumors. Typical symptoms include pigment spots on the skin, scoliosis, learning difficulties and so-called Lisch nodules in the iris of the eye. In this case, what visually looks like partial heterochromia is actually pigmented nodular neoplasms of a benign type;
pigment dispersion - a problem associated with loss of pigmentation on the back surface of the iris, which is reflected on the front surface;
Waardenburg syndrome is a hereditary disease that is accompanied by displacement of the inner corner of the eye, hearing loss from birth, the presence of a gray strand above the forehead and various types of heterochromia; Hirschsprung's disease;
piebaldism - a person with this diagnosis has white spots on the body (including the eyes) from birth, completely devoid of pigment;
iron deposits in the tissues of the eye - siderosis;
a tumor that can also be localized in the brain;
melanoma can also in some cases provoke a change in the color of the iris;
Fuchs' iridocyclitis. The phenomenon explains the dependence of inflammation inside the eye and subsequent atrophy of the iris, which leads to “difference of eyes.”

This is interesting: How to hit a good shot: exercises and training

Layout of the eye color of the unborn child

In order not to get confused in explaining the genome, an approximate general table was adopted in order to determine the eye color of the unborn child. According to her:

2 brown-eyed parents will give birth to a brown-eyed child in 75% of cases, green-eyed in almost 19% of cases, and blue-eyed in only 6% of cases.
With brown-eyed and green-eyed parents, a child in 50% of cases will have brown eyes, in almost 38% of cases - green, and only in almost 13% - blue.
A brown-eyed and blue-eyed parent will again have a brown-eyed child in 50% of cases, and a blue-eyed child in the remaining 50% of cases. A green-eyed child cannot be born to such parents in any case.
Two green-eyed parents will give birth to a child with green eyes in 75% of cases, blue-eyed in 24% of cases, and brown-eyed in only 1% of cases.
A green-eyed and blue-eyed parent will have equal chances of giving birth to a child with blue or green eyes; they cannot have a brown-eyed baby.
Two blue-eyed parents will have a blue-eyed child in 99% of cases and a green-eyed child in only 1% of cases. Brown eyes cannot work here either.

Interesting facts include the following cases:

The majority of the world's population is brown-eyed, and the least number of green-eyed people is observed - only 2% of the total number, and green-eyed female children are most actively born in Turkey and Iceland.
You can hardly find green-eyed people in Asian, South American and Middle Eastern countries, but blue eye color is very common among Caucasians.
The formation of eye color is completed only by the age of 4, and all newborns are born with the same blue eye color, only for some it darkens or turns into other shades.
Brown eyes are blue eyes covered with brown pigment. Modern medicine has reached the point where there is an operation to change eye color from brown to blue, although this will not affect the offspring.
Some scientists believe that blue eye color is due to a genetic mutation, so all blue-eyed people have one common ancestor.
Albinos have red eyes due to the lack of iris pigment.
Black or yellow eyes are actually brown and green, respectively, but the rays falling on them reflect the color differently.

Thus, you can predict the eye color of your unborn child with a high degree of probability. In rare cases, children may be born with different colored irises in both eyes, but this is not a disease, just a unique feature.

What the child will end up with depends 90% on genetics and only 10% on chance. The color of the iris is determined by the concentration of melanin (coloring pigment): if there is little of it, the color is blue, if there is a lot - brown, the remaining shades are located between these colors.

Melanin protects the eye from exposure to ultraviolet rays; the fat-like substance cholesterol and the amino acid tyrosine are involved in the process of its formation.

How eye color is inherited and why some people have different colored eyes

Find out how eye color is inherited and why some people may have one eye brown and the other green.

It is believed that all children are born with gray eyes, and only after a few months it becomes clear whose eye color the baby inherited. But how surprised the parents are when it turns out that his eyes are different.

Natalya Beglyarova, a geneticist, an expert at the Center for Molecular Diagnostics (CMD) of the Central Research Institute of Epidemiology of Rospotrebnadzor, told Letidor what the color of a child’s eyes depends on, whether brown-eyed parents can have a blue-eyed baby and why eyes come in different colors.

What determines eye color

The color of the iris depends on the amount of pigment in it - melanin. The more pigment in the iris, the darker the eyes will be.

So, those with brown-black eyes have the maximum amount of pigment.

Why are the eyes different colors?

Sometimes we come across people with different colored eyes. For example, one is brown and the other is blue or green. This phenomenon is called heterochromia.

It is not so rare, occurring in every hundred people, and means that one eye has an excess or deficiency of pigment.

Heterochromia can be:

- complete, when each eye has its own color;

- sectoral, when one eye has several areas with different pigmentation;

- central, in this case the iris consists of several full-fledged colored rings.

How is heterochromia transmitted?

Heterochromia can be of two types: congenital or acquired.

The latter occurs as a result of various injuries (from fragments of metal objects), disruption of innervation (supply of the organ with nerve cells - editor's note) or inflammatory processes.

Congenital heterochromia can sometimes be a sign of some hereditary diseases. But most often this is an absolutely harmless feature caused by mutations in genes that affect the distribution of melanin in the iris.

Mutations, which actually characterize all genetic characteristics, can occur at different stages of development. This is what determines whether it will become hereditary.

If a mutation occurs in an embryo, say, in the fifth week of development, when the rudiments of the eyes are formed, then it concerns only the tissue of its eyes, which means it will not be passed on to offspring.

But the mutation could arise at the time of conception or at an earlier period of development, at the stage of zygote formation, when fertilization of the egg occurred and division began.

And if it arose in one of the genes that is responsible for the distribution of melanin, then all cells will contain this mutation and it will be inherited.

And when this child grows up, he may have children with different colored eyes.

It is impossible to determine at what stage the mutation occurred, and there is no clinical feasibility in this.

How is eye color transmitted?

It is also impossible to predict what kind of eyes a child will have. Eye color is polygenic in nature, that is, it depends on a large number of genes, on variations in genetic sequences.

It is generally accepted that the genes responsible for dark eye color are dominant, and those responsible for light eyes are suppressed. But in reality, everything is much more complicated and there can be a lot of combinations.

In recent studies, scientists have identified regions in six genes that can reliably predict the eye color of an unborn child.

The most accurate colors to predict are brown and blue. Gray and green are intermediate and are more difficult to predict.

But here again the question of expediency arises. Theoretically, to find out the color of the baby's eyes, the expectant mother will have to make a puncture and remove the amniotic fluid, which contains the genetic material of the fetus. The procedure is quite risky; it is prescribed only for medical reasons (for example, if a chromosomal pathology of the fetus is suspected).

It is basically impossible to plan the birth of, say, a blue-eyed baby.

You can only take into account the statistics according to which, in 75% of cases, with brown-eyed parents, a child will be born with the same eye color. There is a small chance that the baby will have green eyes (18%) or even blue eyes (7%).

If one of the parents has blue eyes, and the other has brown eyes, then the child, with varying degrees of probability, can receive both father's and mother's colors. The same applies to those with blue and green eyes.

If one of the parents is brown-eyed and the other is green-eyed, then dark eyes often “win.”

But genetics never gives one hundred percent certainty. And there remains one percent in which even brown-eyed parents can have a child with blue eyes.

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Formation of eye color

Children are born with blue or brown eyes, and after 6 months the color can change due to exposure to sunlight and genetic factors. Usually, in brown-eyed babies, the color does not change, and the more melanin accumulates, the darker the color of the iris will be.

By the age of 3–4 years, the baby’s eyes acquire a permanent color that remains for life.

You can see other options in which eye color changes.

It is impossible to predict for sure what eye color a baby will have: each child has one version of the same gene: maternal and paternal (these genes are called alleles). One of them will be dominant (predominant), the other will be recessive.

For example, if mom has blue eyes and dad has light green eyes, the child will have the following probability: 60% - eyes will be blue (since the blue tint is dominant), 40% - light green.

Eye color can be passed down through generations

(from grandparents), not only color is also inherited, but also inclusions on the iris.

The shade of eye color is influenced by other genes that are responsible for skin tone and hair color. For example, blond people with fair skin are characterized by light shades, blue eyes are typical.

Representatives of the Negroid race - people with dark skin and dark hair - are characterized by brown eye color.

The gene that is responsible for coloring the iris of the eyes blue or brown is located on chromosome 15; the gene that carries information about green and blue colors is on chromosome 19. The pigment of the iris of the embryo is formed already at the 10th week of gestation.

Eye color also depends on the following factors:

Distribution of melanin pigment in the posterior (ectodermal, external) and anterior (mesodermal, internal) layers of the iris;
Iris fiber density.

Eye color may change in bright light or extreme cold.

In children, the shade may darken and become cloudy after waking up and crying; this phenomenon is called a “chameleon”.

A person has different eyes - what does this mean?

A person's eyes are the mirror of his soul. By eye color you can determine the character and psychological characteristics of a person. However, there are people whose eye colors are different. Different eyes are a phenomenon noted in 1% of the world's population. This phenomenon in medicine is called heterochromia. It manifests itself in the fact that one eye is partially or completely different from the other in color. This phenomenon is caused by a lower content of melanin pigment in it, compared to the other eye. It is melanin that colors the iris of the human eye. If a person has different eyes, the content of melanin pigment in the iris of the lighter one is significantly reduced. As a result, it becomes lighter than the other.

Why does such a phenomenon as different eyes exist? What causes a person's eyes to become different?

If a person has different eyes, this feature is often congenital. However, heterochromia can occur in a person during life. In this case, you should consult a doctor, because this may be the result of various diseases. Firstly, the reason that a person has different eyes is a lack or excess of melanin pigment. This may indicate the presence of the following diseases: glaucoma, inflammatory processes of the iris caused by rheumatism, influenza or tuberculosis, as well as the development of a benign tumor in the human body. In addition, different eyes can also appear as a person’s reaction to drugs and medications.

Another cause of heterochromia is untimely removal of an iron or copper fragment due to eye injury. In this case, the iris may change its color.

It may turn blue-green or rusty brown. These are the main reasons why people have different eyes. The color of the iris can be restored if heterochromia is acquired. For example, if you remove a foreign body in case of eye injuries or cure inflammatory processes.

Heterochromia has two types. It can be complete or partial. Partial heterochromia manifests itself in the fact that the human eye is immediately painted in two colors, that is, one part of the iris will have one shade, and the other will be painted a completely different color. Complete heterochromia of human eyes is two eyes of different colors that differ from each other.

Many people think that heterochromia - different eyes in a person - can affect their health or perception of the world around them. However, this is a misconception, since, fortunately, in most cases, people with such a phenomenon as different eyes do not feel any inconvenience and do not experience health problems. However, there are exceptions when people with light-colored irises may develop a chronic inflammatory process. This process can negatively affect a person’s vision. Therefore, people even with congenital rather than acquired heterochromia need to periodically visit an ophthalmologist’s office. Colors are perceived by people with different eyes in the same way as by normal eyes. Women are more susceptible to the phenomenon of heterochromia than men.

Heterochromia

Heterochromia (multiple-colored eyes) is a condition in which the eyes differ in color or the iris has different colors (partial heterochromia).

This feature is individual and natural.

- a peculiar play of nature, but it may also indicate some ophthalmological diseases (disseminated melanoma, inflammation of the iris), so it is important to be periodically examined by an ophthalmologist.

It is difficult to predict what eye color a baby will have, since modern science has not fully studied the processes taking place.

Even the most experienced geneticist will not be able to predict with 100% certainty the shade of the iris, not only because there are a number of reasons that can change the color, but also because there are exceptions to the rules.

It is impossible to make a mistake only if both parents have blue eyes: the baby will definitely be born blue-eyed.

Probability percentage

Brown-eyed parents are more likely to give birth to a baby with a dark shade of the iris. The chance of his eye color being blue is approximately 6%. Green - 19%. But what if the mother and father are blue-eyed?

Fans of Agatha Christie may remember the novel in which the all-knowing Hercule Poirot managed to expose a fraudster thanks to his knowledge of genetics. The woman posed as the daughter of a wealthy couple, and her scam would have been a success. If it weren’t for the color of the impostor’s eyes, they would have been brown. The people whom she called her parents passed away and could not refute her words. However, Poirot found out that they were blue-eyed. And in this case, the probability of a child being born with brown eyes is zero.

What eye color do you and your children have?

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