Question

Concentration of skin melanin is controlled by
(a) Heredity
(b) Environment
(c) Both heredity and environment
(d) Food

Answer 1

Skin melanin concentration is regulated by factors such as UV rays and also due to gene modifications that are ultimately passed from parents to offspring. Sunlight is the main cause of the increased production of melanin.

Complete step by step answer:
Melanin is a pigment in melanocytes or skin cells formed within the skin when they are exposed to the sun. The mechanism through which the melanocytes form the pigment melanin is referred to as melanogenesis. At least 6 genes decide the color of the skin. Therefore, the color of the skin or complexion is regulated by the environment and also hereditary.
Melanin development is affected by UV exposure, genetic make-up, melanocyte size, and the conditions of the disease. By rapidly darkening existing melanin, and by inducing melanocytes to create more pigment, factors such as sunlight, UV light from sun lamps, and X rays influence skin color. Skin color is affected by the dermal blood supply.
So, the correct answer is, ‘(c) Both heredity and environment’.

Additional information: For a group of natural pigments present in most species, melanin is a broad term. Melanin is formed by a multistage chemical process known as melanogenesis, in which polymerization follows the oxidation of the amino acid tyrosine. Although human beings have a similar concentration of melanocytes in their skin in general, melanocytes contain varying amounts of melanin in certain people and ethnic groups. In their bodies, certain humans have very little to no synthesis of melanin, a disorder known as albinism.

Note: There are several different melanin forms of different proportions and bonding patterns of these component molecules, since melanin is an aggregate of smaller component molecules. In human skin and hair, both pheomelanin and eumelanin are present, but eumelanin is the most abundant melanin in humans as well as the type most likely to be deficient in albinism. There are about nine types of oculocutaneous albinism, which is mostly an autosomal recessive disorder. There are higher incidences of various types of ethnicities. For example, among people of black African descent, the most common form, called oculocutaneous albinism type 2, is extremely frequent. It is an autosomal recessive condition characterized in the skin, hair, and eyes by a congenital reduction or absence of melanin pigment.