While expecting a child, parents think about what the eye color will be and who they will look like.
The tone of the organs of vision is influenced by many factors; it can be calculated.
Hue is a physical trait determined by the eyes of the parents.
A child inherits 50% of his genetic material from his mother and father. Genes mutate to produce alternative forms called alleles, and each allele is different from the other.
The tone of a newborn's iris depends both on the color of the parents' visual organs and on whether the alleles are dominant or recessive. It is affected by the amount of melanin.
What determines the color of a child's iris?
Texture, pigmentation, tissue and vascular factors in the organs of vision. They constitute a unique characteristic of a person.
What determines the color of a child’s eyes is of interest to new or expectant mothers and fathers.
There are 2 conditions that help determine the tone: the amount and pattern of dark brown pigment (known in medicine as melanin) in the part of the visual organs located between the cornea and the lens.
What role does melanin play?
Melanin is produced by cells called melanocytes. This is a pigment that is responsible for the tone of the skin and eyes. Just as sunlight turns the skin into a dark tone, it does the same with the tint through the iris. When a baby is born and exposed to bright light, this light triggers the production of melanin in the choroid, which leads to a change in color.
Excessive accumulation of melanin leads to the development of pathological conditions and irreversible changes in the tone of the iris.
Genetic trait
Color inheritance comes from mother and father. Genetics plays a significant role. Normal diploid cells have 46 chromosomes, divided into 22 pairs of autosomal chromosomes and a pair of sexual chromosomes, X and Y. The embryo (early stage of human development) inherits one from each.
Human cells are composed of fragments of deoxyribonucleic acid. Scientists have discovered that up to 16 material carriers of heredity take part in determining color. OCA2 and HERC2 are considered responsible for this; they are part of the 15 nucleoprotein structure in the nucleus of eukaryotes. Genes consist of different forms of the same gene located on the same homologous chromosomes.
For each trait that the baby will inherit, there are 2 allelic genes. If they are similar, they are called homozygous. If they are different, then they are heterozygous. For each trait, one allele (dominant) is expressed, while the other (recessive) is not expressed (the trait it represents does not appear). Recessive ones are expressed only in the absence of a dominant one.
Alleles for shades are usually divided into blue, green and brown. Greens suppress blues, and browns suppress greens and blues. If the baby got blue and brown, the eye color will be brown because it is dominant. If a daughter/son has a blue iris, this means that he received blue alleles from his mother and father.
Genes determine color. The material carrier of heredity determines how much melanin is produced in the iris. The more pigment produced, the darker the color. Because melanin production begins at birth, babies' irises appear blue.
It follows from this that heredity affects the shade of the newborn’s visual organs. It is transmitted from parents along with DNA fragments contained in chromosomes.
Have you noticed how people's irises change depending on the brightness of the room? This happens because the choroid is made up of two layers. Sometimes the pigment is present in both layers. Depending on the brightness and diffraction of solar energy perceived by the organ of vision, it can change color.
On some faces they are of different tones. This occurs due to a condition called heterochromia.
When the color changes
The most dramatic changes in tone occur when the baby is 6–9 months old. At this point, enough pigment has accumulated to predict what the final shade will be. But there is a high probability that the color will change.
Green eyes slowly turn to brown, or brown to brown. Changes will occur until the age of three. In approximately 10% of the population, eye shade can change in adulthood.
The baby's eyes will remain blue
Most newborns have blue irises, which may change color over time. Eyes remain blue if both parents pass on their recessive blue genes to the baby. If this is not the case, the color changes to permanent (brown, green or any other).
Most babies of Caucasian origin have dark blue eyes at birth. However, the original tone changes.
Similarly, babies of Asian and African descent have a brown or dark gray tone at birth. Over time they turn black or brown.
Eye color - what factors does it depend on?
- 2.1 Video: When a child’s eye color changes and why
- 6.1 Video: What color eyes will the child have?
According to Gregor Mendel's law on the transmission of hereditary characteristics, a child is transmitted from his parents not only appearance or characteristic behavioral traits, but also eye color . This pattern can be explained by the structural features of the iris, or more precisely, by the presence of melanin pigment in it and its quantity. This pigment is also responsible for the appearance of a person’s skin and hair color.
What determines eye color
Note! By studying the color spectrum, scientists have found that blue eyes, due to a small amount of melanin, in most cases are at one pole. And due to the large amount of pigment, brown eyes, accordingly, will be on the other. If we talk about all other colors, they are approximately in the intervals between the previously mentioned poles.
What is eye color
You can predict the eye color of your unborn child using the necessary table and the results of numerous scientific studies, but such information cannot be called absolutely reliable, so parents should not be surprised later that the results of their calculations did not coincide with the appearance of the newborn. According to statistics, 9 out of 10 babies have blue eyes at birth, but over the years the color of the iris may change . This is normal, so if your baby's eyes gradually change color, don't panic.
Eye color, what does it depend on?
Age-related changes are associated with the fact that melanin accumulates in the iris on an ongoing basis until the eyes change to a shade determined by genetics. As a rule, such changes are observed as early as 12 months of age, but there may be exceptions. The complete transformation of eye color reaches its final stage, usually at the age of 2 to 3 years, sometimes the process drags on up to 4 years.
Melanin is a special pigment
Video: How to find out the eye color of your unborn child
Table of possible eye colors for a child
You can calculate the color of a child's eyes. There is a table with which modern society is able to determine the shade of a baby’s iris.
On the left side is a combination of the father's and mother's eyes. They are depicted in the form of color drawings. The right column shows the iris tone that a newborn will get. The percentage is indicated below them; it means what color the baby is most likely to get.
For example:
- Both parents have brown eyes - the probability that the child will have the same is 75% (brown is dominant, which is why babies rarely have blue eyes).
- If one parent is green and the other is brown, the latter is dominant, green is recessive. This means that as the baby grows older, there is a greater chance of getting a brown tone - 50%, and only 37.5% is allocated to the fact that the newborn will have a green iris.
- If the mother and father have green eyes, then in 75% of cases the baby will have a similar color, in 24% - blue and 1% chance of brown eyes.
Information on other options is understood in the same way.
Yellow eyes are very rare. This variation occurs when there is an excess amount of lipofuscin (this is the end product of oxidation within cellular lipids and proteins). More often than not, this tone indicates the presence of kidney disease.
Amber shades are also associated with excess lipofuscin. Eyes can be light amber or dark.
Black eyes in a newborn mean an excess amount of melanin. There is so much of it that light rays are almost completely absorbed. This color type is common among people of the Mongoloid race, in East and South Asia.
Blue-eyed child with brown-eyed parents
Brown-eyed parents can have a blue-eyed child if both have recessive genes in their genomes that are responsible for light eye shade. In this case, part of the germ cells gets the dominant, which manifests itself in the form of brown eyes, and the other part gets the recessive gene. If, during conception, cells with genes for light eyes meet each other, then the child will have light eyes.
The probability of such an event is about 25%.
Much less common are situations where brown-eyed children are born to blue-eyed parents. From the point of view of the simplified laws of genetics described above, it is impossible to explain this: where could the dominant gene come from in the baby, if it does not appear in the parents, then they do not have it? And yet such cases exist, and geneticists easily explain this.
In fact, the principles of inheritance are much more complex than they seem. In humans, not one pair of genes is responsible for eye color, but a whole set in which genes inherited from many previous generations are mixed. The combinations can be very diverse, so you can never predict 100 percent what kind of eyes a child will have. Even scientists still cannot fully understand inheritance patterns: eye color can be influenced by a variety of genes in different parts of the chromosomes.
Exceptions to the rules
According to Mendel's laws, dominant genes suppress the totality of biological properties and characteristics of an organism with light-colored recessive genes. It is believed that dark-skinned people give birth to the same baby, the same goes for hair and color.
Not only parents, but also close relatives can influence coloration. Grandparents also influence skin and eye shade. If light-colored parents gave birth to a dark-skinned baby, it means there was a dark-skinned great-grandmother in the family. This also applies to babies with eye colors different from their parents.
Some babies have violet-colored visual organs. This is due to the lack of melanin in the iris. This phenomenon is normal. Such eyes are incredibly beautiful and attractive.
You should be concerned if your eyes are different colors and there are other signs indicating the development of a disease. For example:
- Heterochromia is a rare condition in which a newborn's eyes have two different tones. The cause is believed to be a gene change that leads to excessive pigmentation in one of the irises. In rare cases, different colors of different parts of the iris of one visual organ are observed.
- Waardenburg syndrome. A gene mutation occurs that causes changes in the level of pigmentation of the hair, iris and skin. Waardenburg syndrome is also accompanied by sensorineural hearing loss in some children.
It is important to know that eye color changes depending on the color of clothing, environment, stressful situations and emotional turmoil.
