Table of contents:
- The main reason is melanin
- Why doesn't frequent exposure to sunlight cause a change in shade? 2
- Genetic factors3
- Can you have different colored eyes? 4
- What are the experts saying? 5
- Studies of the relationship between the character and the hue of the iris
- Dark (black, brown) eyes 8
- Brown and amber eyes 9
- Blue eyes 10
- Green eyes11
- Eyes gray12
Video: What Determines The Color Of A Person's Eyes? How Does It Affect Character?
Blue, gray, green, hazel, dark brown - how many people are in the world, so many shades of iris color. Where do they come from and do they depend only on the distribution of pigment in the iris? What else affects eye color?
The content of the article
- 1 The main reason is melanin
- 2 Why does not frequent exposure to sunlight cause a change in shade?
- 3 Genetic factors
- 4 Can I have eyes of different colors?
- 5 What do the experts say to this?
- 6 Research
- 7 Studies of the relationship between the nature and shade of the iris
- 8 Dark (black, brown) eyes
- 9 Eyes brown and amber
- 10 Blue eyes
- 11 Eyes green
- 12 Eyes gray
The main reason is melanin
The hue is in direct proportion to the content of the pigment melanin - a dye that is present in the skin in different quantities in different people. The color of the skin and the possibility of fast or slow tanning, hair color, the number of moles on the skin and just the color of the eyes depend on it. The stronger the concentration of the dye, the darker this shade.
Dark-haired people often have a dark iris, therefore, the dye is found in large volumes, blondes and redheads have it several times less. In addition to the aesthetic issue, which manifests itself in the coloring of the skin and hair, melanin performs an additional function - it receives ultraviolet rays (this is the reason for sunburn). When it comes to the shade of the skin and hair, this dependence is very simple; in the matter of eye color, slightly different rules rule. Nature often shows that eye color and skin color do not always go hand in hand with each other.
In addition to the content of pigments in the iris, the density of the cells of the stroma of the iris affects the shade of the eyes. In turn, the density of the iris stromal cells determines how much light is absorbed by the main pigment of the epithelium.
Why doesn't frequent exposure to sunlight cause a change in shade? 2
The pigment in the organs of vision has completely different properties than in the skin. When a person is often under the sun's rays, he does not have the slightest chance of changing the color of his eyes from lighter (blue) to dark (brown or dark brown). And the point here is that the defense mechanisms of these organs do not create opportunities for the influx of ultraviolet rays into these sensory organs (nature gave a person a reflex to lower their eyelids in bright light).
In addition, the cornea concentrates the sun's rays, preventing them from passing through the entire iris. Otherwise, it would carry the risk of damaging the light-sensitive structures in the eye and losing its ability to function normally.
Heredity plays a large role in determining the shade of the iris. Brown-eyed people in all cases will have dark-eyed heirs or (less often) they may have a green-eyed child. Individuals with blue irises are capable of having both light-eyed and green-eyed children. This happens due to the inheritance of genes that determine the formation of the required amount of dye in the iris. And the color of the baby's eyes changes after the first six months of his life. So it is necessary that he gradually produces the required amount of pigment. The shade gradually changes to a darker one.
Can you have different colored eyes? 4
Of course, this is not very common. Just like the uneven distribution of the dye in the eyes (brown around the pupil, and blue on the rest of the iris). This is not considered a sign of a disease, although it can often be a sign of genetic abnormalities and may predispose to the development of vision diseases in the future. Only a professional who has subjected the senses to research is capable of refuting such risks.
Several genes have an impact on the shade of the iris. Their combinations lead to the appearance of different shades or difficult to uniquely identify colors.
A simplified theory of the inheritance of eye color that people learn in school suggests that when the dominant gene takes over, the person tends to have dark eyes, and when the recessive gene takes over, blue. If the father has a recessive gene and is dominant, then there is a 50% chance that the offspring will have dark or light eyes. If both parents have blue eyes, their child will not have dark ones. Such a pair has two recessive genes, and, therefore, they cannot pass on the dominant genes to the child.
What are the experts saying? 5
In fact, this shade is due to the amount of melanin and the ratio of eumelanin (dark brown dye) to pheomelanin (reddish dye). The genes OCA2 and HERC2 play the most important role in determining the color of the iris, but, in addition to the listed ones, at least 10 other genes are known that affect this characteristic. Ultimately, the interaction of all of them determines the end result. Thus, parents with blue eyes can have children with brown irises. All babies are born with blue eyes. Eye color usually stabilizes around the sixth month of life.
In 2006, the molecular basis of EYCL3 was analyzed. Studying a group of 3,839 people, the scientists found that 74% of all variations in eye color can be attributed to single nucleotide polymorphisms (SNPs) in the OCA2 gene, which, if mutated, can cause albinism. Recent studies have shown that SNPs are strongly associated with blue and green eyes, freckles, hair and skin tones.
Eye color is found in different variations from black tones to sky blue. Seeing the need to standardize a classification system that is simple yet detailed and easy to research, anthropologists have developed a graded system based on identifying the dominant shade in the iris. First of all, the presence of brown and yellow pigments is taken into account.
It is assumed that people with a certain dominant eye color live in certain geographic areas of the world. For example, Asians have very dark eyes, while typical Slavs are blue or gray. Sometimes it is difficult to determine what kind of eye color someone has. It changes with the lighting.
There is also a system based on 3 main colors: brown, yellow and gray, their proportions determine the color of the eyes. For example, in light brown irises, yellow dominates, and there are elements of brown dye, blue ones have very little yellow dye and do not contain any particles of brown, green, like blue eyes, have a fairly large amount of yellow pigment. Gray eyes are exactly this shade, because they have little yellow, although they contain small blotches of brown dyes. Brown eyes look like this because they contain a lot of brown dye.
Dark eye color is recognized as the most common (90%), blue is in second place (7%), the ratio between gray and green is close, but most often it is believed that 2% of the population has a gray tint, and green is the rarest (1%) …
The mixture of pigments takes the form of a more or less uniform distribution of different shades in the iris of the eyes (mainly in the form of spots). Sometimes it appears in a light iris surrounded by a thick brown border. With lighter shades, sometimes small blotches of brown pigment in the form of spots or a narrow rim around the pupil come across.
Purple is found in the eyes as a result of mixing red and blue reflections. In reality, these people may have shades of blue irises that, under the influence of light, blood vessels or appropriate makeup, may simply resemble a purple hue.
One scientific explanation also suggests that violet eyes are associated with people with albinism. They are born with no pigment in the skin, hair and iris of the eyes. The lack of pigmentation causes their eyes to take on a purple-blue or red tint.
Studies of the relationship between the character and the hue of the iris
Scientists have made more than one attempt to prove that the shade of the eyes indicates certain personality characteristics. They investigated whether the color of the iris in part determines certain behaviors. Scientists from Sweden explain that the eye has many neurological connections to the brain and therefore there may be an unusual combination of iris color with character.
Dark (black, brown) eyes 8
People with dark eyes are supposed to be natural born leaders. Even if they don't realize it, others more often intuitively sense a strong personality in them. The dark color of the iris means that there is a large amount of melanin in the body, and therefore much more energy. Black-eyed people's genes enable them to overcome more adversity, and their brains work more efficiently and faster. There are also some cryptic statements.
Interestingly, it has been proven that people with dark eyes need less sleep than others, but it is much more difficult to get up in the morning. An additional feature is a well-developed self-confidence and the ability to be pleasant to others.
Brown and amber eyes 9
This color is considered the most difficult to describe because the hue takes many different forms. He sometimes approaches the green, other times he is golden. According to scientists, this complexity translates into a complex personality. People with this color of eyes are, of course, unique, sensitive, rather mysterious. Characterizes their independence and self-confidence. Show great spontaneity.
And according to researchers in Australia, this unique eye color is a result of liver dysfunction, so it's no surprise that people with brown eyes are more likely to have digestive problems.
Blue eyes 10
Those with blue eyes are undoubtedly sexy, but not necessarily highly intelligent. They tend to constantly experience ecstasy. They are very strong inwardly and can take more than people with a different iris color. They also have a sober head and alcohol does not do them as much harm as other people. Scientists have also found that, despite their apparent openness, they are rather lethargic.
This is the rarest and most unique shade. According to research, the green tint of the iris is considered the sexiest and most attractive to the people around. People with a green tint are few, they are considered outstanding and very intelligent.
They are usually calm, although they have a lot of energy and are very creative. The lack of time is not terrible for them. They can be good and responsible friends and loyal partners for life. Even though they are usually calm, they can afford a little madness and extravagance.
Green irises are recognized as the result of the presence of a small to moderate amount of melanin, making them appear blue eyes with small dots of a different color distributed over the iris in close light. Blue and brown together give green, but no green pigment. If the amount of pigment increases slightly, it may block the blue. If the pigment covers the blue completely, the eye may turn brown. Green irises are not common, but are most common among Europeans, particularly among the Irish and people in northern European countries. Among European Americans, green eyes are most common among those of Germanic descent.
They are the prerogative of creative individuals with a strong personality, but a sensitive soul, ambitious and able to cope with any situation. They approach everything with great responsibility, do not rest on their laurels, constantly strive to give their all more and more. They have very developed imagination and creative thinking.
Individuals with gray eyes are brave in their professional lives, but have problems with courage in their personal lives. Often they are loners, isolated from others and cannot decide on a lasting relationship, because they show too much caution in the relationship between a man and a woman.
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