30,000 years ago, the Earth experienced several important glacial periods. Therefore, our ancestors had to travel across the 5 continents in search of food. During their search, they got use to new climates and gradually, they changed physically, altering their skin colour. This is due to the amount of small coloured granules present in the epidermis layer (upper layer of the skin), which explains the extraordinary diversity of existing skin colours.
These granules are the melanin pigments, which are produced continuously by epidermal melanocytes. The greater the presence of these pigments in the skin, the darker it is. Depending on the different skin colours, the melanin granules are distributed in different ways: in clear skins, they form small isolated packages and in dark skin, they are distributed throughout the cells of the epidermis. Melanin pigments are controlled by the genes inherited from our parents through the activity of the melanocytes.
Melanin gives colour to the skin but it also protects against the sun. It absorbs part of the ultraviolet rays, which are responsible of our sunburns. Melanin is a natural filter, more or less activated in function of the sunshine. In some parts of the world, where the sun’s rays are stronger, dark skin protects better than a clear skin: our body evolves according to the environment over time.