Humans are of different colors, some are light skinned while others are dark skinned. What makes us have different skin color? The answer is melanin.
What is melanin?
Melanin is a complex polymer that is derived from the amino acid tyrosine. It is a group of complex polymerix pigments which exist in our bodies that is beneath our skin and in an array of different forms.
Type of melanin
There are three different types of melanin
Eumelanin is melanin that is found in the hair, skin and the dark areas around the nipples. It is commonly found among dark skinned people which also provides the black and brown pigment found in the hair, skin and eyes.
Pheomelanin is found in the skin and hair also. It gives red haired individuals the pink and red pigment. Pheomelanin is not protective against the harmful UV rays compared to eumelanin.
Neuromelanin is melanin found in different areas of the brain and loss of neuromelanin may lead to several neurological disorders.
How is melanin produced?
Melanin production requires the use of at least 6 routes which are controlled strictly by several protein enzymes and if one of these proteins is missing then melanin will not be produced. The 6 routes stimulate a messenger which activates genes in the melanocytes nucleus that helps to increase production of melanin.
Melanosomes are made by melanocytes which are made of fiber like network foundation laid by a special protein called Pmel17 which is unique to melanocytes. Since melanosomes are organelles, it requires a whole organelle specific to a cell type in order to have a complete transfer to a different cell. Melanocytes achieve this by forming long arms that extend to the skin cells. Inside the arms, there are microtubules that act like railroad tracks and help to pull melanosomes outward by help of tiny protein motors.
The melanosomes are put in a vesicle and controlled by four carrier proteins and are transferred to the tip of the arm. These tips fit into invaginated spots in the skin cell where the melanosomes are injected. This is followed by the skin cells conveying the melanosomes to the sunward side of the nuclei.
Melanin affects our skin in different ways.
1. Protection from harmful UV rays
Sun bathing at the beach or by the pool is one way of gaining Vitamin D. Vitamin D is useful to the body because it helps make the teeth and bones strong. This is usually as a result of good UV rays which means you need to be exposed for a short while in order to get these benefits.
UV rays become harmful when one exposes themselves for too long in the sun and when the UV rays are projected at a certain wavelength. The harmful UV rays may cause premature aging and other various skin cancers such as basal cell carcinoma or melanoma.
The ability of your skin withstanding the harmful effects of UV rays depends on the amount of melanin present on your skin. The number of melanocytes in the epidermis determines the amount of melanin one has in the skin.
In light skinned individuals, melanin production is increased when the body is exposed to the sun which results in what is called tanning. In dark skinned people, the effects of UV rays may be felt less due to the availability of more melanin.
2. Prevent damage by free radicals
Free radicals are molecules found in the body and are usually missing a part. They injure normal cells making them to grow abnormally. Free radicals have been found to contribute to widespread damage of body cells.
Melanin helps to scavenge the free radicals therefore preventing damage to the skin which is the intention of free radicals. Free radicals attack the skin cells by affecting the lipids which hold moisture and are located in the stratum corneum. It is the outer layer of epidermis. When skin loses moisture, it will become rigid and cracks. Melanin prevents this from happening.
3. Provide color to a person
Melanin helps to create pigment which helps to identify whether a person is dark skinned or light skinned. Lack of melanin or production of colorless melanin leads to albinism. This is why albinos need sun screen and hats when stepping out in the sun. Their skin is sensitive to sun exposure and may cause skin cancer.