Have you ever wondered what Melanin is? Or wanted to know what it’s role is? Then wonder no more. So you already know you can find it in the human body. But the biological pigment known as melanin determines the colour of both hair and skin. Different forms are prevalent throughout the animal world determining their colour. For example, melanin is found in the wings of birds and it determines the wing colouration. Cells called melanocytes produce melanin. Melanocytes are also capable of responding to changes in the environment. For example they can increase and decrease production depending on the amount of exposure to sunlight.
How is Melanin Produced?
Melanocyte cells located in the outermost layer of the skin known as the epidermis produce the melanin. These melanocytes live on the lowest layer of the epidermis known as the basal layer. People with lighter skin tones do not have any more or less melanocytes than those with darker skin. In fact, a higher fraction of the genes in melanocytes that are responsible for melanin production are switched on in those with darker skin. Thus meaning people with darker skin produce more.
This has evolutionary implications, because it suggests that lighter-skinned European people of today share deep ancestry with people of Africa whose skin remains darker today thanks to different environmental conditions. Many people from North-western Europe have lost the ability to develop a tan because the strand of DNA they have that codes for additional melanin exists, but can no longer be activated. Therefore ultraviolet (UV) light damage will be much harder to tolerate for those affected. You can learn more about sun protection here.
The Function of Melanin
The function has nothing to do with vanity and everything to do with protecting the body. UV radiation is now a well known carcinogen which can lead to malignant cancerous cells and can ultimately be fatal.
Some humans and animals produce extremely low levels and this condition is known as albinism, and thus those affected are highly susceptible to UV damage.