What are the reasons why people s skin will appear different in color?

The geographical conditions of different regions, the light of the sun, the temperature, the local customs, the biological genetic factors, the amount of melanin, etc. The difference in skin color of people is due to the inconsistency of the amount and distribution of melanin. Melanin is an iron-free brown particle, mostly bound to proteins, and is found in the cells of the germinal layer of the epidermis, or some of them are found between cells.

When the amount of melanin is large and concentrated in the germinal layer in a granular form, the color of ** is black. If the amount of melanin is high and its distribution extends to the granular layer, it is dark black. On the contrary, if the amount of melanin contained in the germinal layer is small and distributed in a scattered state, it is a light color.

Caucasians** have the least amount of melanin, and it is scattered in the germinal layer, so the skin tone is the lightest, so that the color of the subcutaneous microvessels is transparent, and it often appears "flesh color".The early formation of different skin tones is closely related to environmental influences. Anthropologists believe that humans evolved in the southern suburbs of Africa and Asia.

The sun is abundant here, the ultraviolet rays are strong, and the ** of people is mostly black to resist the damage of strong sunlight. With the migration of ancient humans, the skin color of people changed from dark to light, or from light to dark. With the development of human society, the role of geographical environment on the human body has been weakening.

The skin color of different races is also related to genetics. For example, Africans have a black color, a trait that can be maintained in their offspring, and although they migrated to the Americas or Europe, the black color is still inherited. In addition, the mixing of bloodlines can also give rise to new racial types.

The Urals are a mixture of yellow and white people. Dark skin tones have a certain protective effect on the human body, especially in tropical areas, which can make people better tolerate the strong exposure of ultraviolet rays and protect deep blood vessels and other tissues from damage.

The color is mainly determined by the amount of melanin in it. Melanin is a black or brown particle, and its main role is to block the damage of ultraviolet rays in the sun's rays to the cells below the human body**. When the sun is stronger, the amount of melanin increases, so we get tanned in the summer.

The color of human beings is the result of adaptation to nature in the process of evolution. Africans living in the equatorial region are often exposed to strong sunlight and produce a large amount of melanin in their bodies, so Africans are black. In the alpine land less, so, ** is white.

Yellow people generally live in temperate regions, the intensity of sunlight is in the middle, and melanin is also in between, so the color of ** is also between the two people. Scientists have found that there is no difference in the ancestors of human beings at the beginning, and the skin color is basically the same. It was only later that people moved to different regions and gradually developed differences in skin color in order to adapt to the outside environment.

The color of ** is mostly determined by the amount of melanin in **. Melanin is a black or brown particle that blocks harmful ultraviolet rays from sunlight. The color of human beings is the result of adaptation to nature in the process of evolution.

In the cold of northern Europe, people cannot be exposed to the scorching sun, so there is very little melanin in the body; Africans living near the equator, because they are often exposed to strong sunlight, will produce a large amount of melanin in their bodies, so Africans are all black or brownish-black; Most of the yellow people live in temperate regions, so the color of ** is also lighter. Different regions have different environments, and over time, there are little differences, and then the generations reproduce, and the differences in skin color become more and more obvious.

We all know that there are several races in the world, and many of us can distinguish them from the skin color, but many people know why people's skin colors have different colors?

Why do people's ** have different colors

Sociologists or anthropologists often define different races according to the different skin colors of people, for example, yellow people, white people, black people, etc.

The color of human beings is mainly determined by the amount of melanin in it. The content of melanin is different, which also forms people with different skin tones.

In order to adapt to different living environments, human beings have been constantly evolving their bodies, such as melanin, because too much or too little ultraviolet rays are not good for the human body, and melanin is like an "umbrella" that blocks ultraviolet rays.

Therefore, in places such as Africa, where the sun is exposed to more intensely, the higher the melanin content in the human body, and the skin tone of the person will naturally appear black. In places like North America, where sun exposure is less intense, people's skin tone is mostly white.

Our skin color can vary from dark to almost white depending on the ethnic group (white and red is caused by blood in the skin). The hue of the skin tone is determined by the amount of melanin in **. On average, women have slightly lighter skin tones than men.

The main factor contributing to this is the environment in which our ancestors lived.

Usually the ancestors come from the people of the light-rich area, with darker **; People whose ancestors came from areas where there was little sunlight had lighter skin tones. For some ethnic groups with ancestors in different areas of light, it may contain a variety of different shades of skin tones at the same time. In addition, sexual selection also affects the distribution of skin color.

There are two types of melanin, pheomelanin (red) and eumelanin (brown), and their number depends on whether the gene is dominant (in general, they are incomplete dominant). At the same time, absorbing ultraviolet rays also presents melanin in **, so it becomes darker after sun exposure**, even in white people.

In ancient times, humans were distributed in different places. Because the amount of melanin is closely related to the amount of sunlight hours. Therefore, in those places in Africa where the sunshine hours are extremely long, to prevent the damage of ultraviolet rays to **, melanin will continue to increase, and the skin tone of the local people will basically be black.

Most of the ancients did not live to get cancer from ultraviolet rays. However, ultraviolet rays can destroy folic acid, and pregnant women who lack folic acid are prone to give birth to deformed babies, which is the evolutionary driving force for darkening. Ultraviolet rays help synthesize vitamin D, and black** can lead to vitamin D deficiency.

After the birth of agriculture, the food composition of human beings became monolithic, so that vitamin D deficiency made human skin color whiter.

The August 25, 2012 issue of the journal "Molecular Biology and Evolution" published a ** written by several scientists from the University of Porto, Portugal, by analyzing the mutation time of Kitlg, TyrP1, SLC24A5 and SLC45A2 genes, it was found that the ** of Europeans finally turned white thousands of years ago. Another article published in Science in an earlier year dated more recently, 5300 6000 years.

Both Eurasia and the Americas have clearly seen lighter skin tones in people living at higher latitudes, although the Aboriginal Canadians and the northern Aborigines of Siberia have darker skin tones than the Aboriginal people of Northern Europe, because the Nordics use fish oil as a supplement to vitamin D, so they can be whiter. The southernmost blacks in Africa, although much darker than the northernmost Arabs, are still lighter than Africans living near the equator.

After the birth of human beings, they will inevitably continue to migrate, and due to the different places of migration and the different environments in which they live, they will have different skin colors. Those who live in Africa have darkened skin color because of the strong sunlight; In Europe, because the sun is weak, the complexion is white; Asia is in the middle, and so is the skin tone.

The reason for this phenomenon is genes, each person's genes are different, so the results presented are also different, this phenomenon is normal, otherwise people are the same.

1. Reason 1: One of the reasons for blackening is that people's daily diet is related, many people do not pay attention to their diet, and do not pay attention to the combination of nutrition, some foods will make **blacken, these foods mainly include animal offal, shrimp and crabs, as well as soy products, walnuts and black sesame and other foods, so everyone should pay attention to their diet if you want to have a good **.

2. Reason 2: Drugs can also cause people's ** to turn black, and some drugs have an affinity for melanin.

Human skin color will be different, the reason for this phenomenon is that there is a pigment cell in the human body, the skin color is different between different races, but the content of melanin is different, no matter what race, the more melanin produced by pigment cells, the darker the skin tone. The difference in skin color is gradually formed by human beings in the process of long-term evolution to adapt to the environment, and the color of human beings is determined by the four colors of white, yellow, black and red, which are formed in different proportions.

The color is mainly determined by the amount of melanin in it. The amount of melanin contained in people's ** is somewhat different, and people of different skin colors are formed.

The more melanin you have, the darker your skin tone. People with light skin who stay in the sun for a long time will produce a lot of melanin, in other words, the person is sunburned. People with albinism do not have melanin in them, and their color is usually pink, which is actually the color of blood through the colorless color.

Today, human beings are found in all corners of the world, and the color of people's skin reflects the climate conditions of the world: in Scandinavia, where there is little sunlight, the inhabitants have the lightest skin tone; Residents of sunnier areas,** appear golden or pale brown; The indigenous peoples living in Africa and Australia have the darkest populations.

Now the world is divided according to skin color, mainly by the three major races, namely the yellow race, the white race and the black race, although we are all the same species, but our skin color is very different, the difference in skin color is affected by what.

When ultraviolet light passes through the epidermis, photons strike the DNA of the living cells in it, causing some of these molecules to be excited, which in turn induces other reactions, such as the fusion of two adjacent base pairs. Specifically, if two pyrimidine base pairs are adjacent to each other and spatially symmetrical, they may undergo a pericyclic reaction, in which pyrimidines form a four-carbon ring hand-in-hand, which can easily lead to errors in DNA coding and abnormal protein binding.

But now the number of melanocytes in the human body is actually roughly the same, what really determines the difference in appearance is the amount of melanin they produce and the ratio between eumelanin and brown melanin, hair pigment and other pigments, for example, people who mainly produce melanin tend to have brown or black hair, and dark**People who mainly produce melanin tend to have red or blonde hair and light and white**.

For us as individuals, sun protection is not about aesthetics and the pressure of natural selection, some animals have evolved specialized biochemical protection against these DNA damage, eumelanin, a class of molecular proteins, related to the depth and light of human skin tone.

Further research has shown that the type of melanin produced by melanocytes is controlled by the cortin receptor MCR on their surface, and scientists have found that between 1 million and 1.2 million years ago, dark-skinned anecdotes experienced intense sun exposure, which means that humans gradually darkened during this time.

Later, due to the fact that food became more monolithic cereals and the coverage of clothing areas increased, people would face the problem of vitamin D deficiency, at this time, light skin tones could synthesize vitamin D more efficiently, and thus gain a competitive advantage, women need more calcium during pregnancy, so women have a fairer complexion than men.

There are yellows, blacks and whites. The formation of these skin color is mainly due to genetic differences, and other aspects are also manifested in geographical factors and environmental influences.

Through each person's health condition, as well as vitality, different skin color differences are caused, and there will be different skin color conditions.

Because everyone's genes are different, everyone's living environment is different, and the diet they eat is also different.

The color of human color black depends on two factors: first, the content of melanin, carotene and hemoglobin in blood vessels; The second is the thickness of the first thin, the thin epidermis is easy to show the color of blood in the blood vessels, the particle layer is thick, the light transmittance is poor, and the color is yellow.

Melanin is produced by melanocytes and is the main pigment that determines the color, and the change in color is due to the increase and decrease of melanocytes and their dysfunction.

When the lack of melanocytes or the ability of melanocytes to form melanin is affected due to a defect in a certain link in the melanin metabolism process, ** is white, mostly hereditary, such as vitiligo, albinism, etc.

If the skin tone is slightly light, you should pay attention to "pseudohypopigmentation" such as tinea versicolor, simple pityriasis and eczema, etc., due to the light-blocking effect of microorganisms or abnormal keratin on the surface, so that the local skin tone is slightly lighter.

Ethnicity and skin color influence.

The genetic characteristics of skin color are one of the indicators of racial classification, but there are still large differences in skin color within the three major human races. For example, the Caucasian race includes Europeans, Arabs, and Iranians, among which Europeans have the lightest skin tone; East Asian races include people from Central, East and Southeast Asian countries, and Southeast Asian residents have significantly darker skin tones.

Negro-Australians are also often divided into black and brown races, with the Negro race being relatively light-skinned in North Africa and darker in southern Africa. Probably that's the rule.

Indians are more difficult to classify. The earliest inhabitants of the area should be said to be of the East Asian race, but the Aryans of the ancient Caucasian race invaded there thousands of years ago, and later the people of Iran and Central Asia invaded there in large numbers, so it is difficult to say whether the Indians belong to East Asia or the Caucasian.

With regard to skin color and ethnicity, it is important to note that the impact of historical migration and interracial movement has been enormous. For example, the Finns in Europe, from the linguistic characteristics, their ancestors came from the East Asian race in Asia, but the current Finns basically reflect the physical characteristics of the Caucasians.