Firstly, let’s talk about the pigment cells, called “melanocytes”
- Melanocytes are different from the other types of skin cells, in that they originate from what is called the “neural crest” in the developing fetus, and not from the “ectoderm” which gives rise to the other skin cell types and structures. By about the third to fourth month of pregnancy, the melanocytes migrate to the area where the skin cells are developing, and the mature melanocytes take up their position in the basal layer of the epidermis.
- So, do dark-skinned people have more melanocytes in the epidermis than fair-skinned people? Interestingly, no. We all have the same number of pigment cells, but there is a genetic difference in the type of melanin or pigment produced.; Dark-skinned people produce more of a type of melanin called Eumelanin that has black and brown forms. This type of melanin is responsible for skin and hair color that is dark brown to black, and is the predominant melanin in dark-skinned people. On the other hand, fair skinned people have a predominance of Pheomelanin which is yellowish to reddish, and hence people of fair to red complexion.; The enormous range of skin colors in humans is therefore a result of genetic proportioning of these two types of melanin.
- So why do dark-skinned people not get as many skin cancers?; The reason is that the Eumelanin in their skin is an excellent natural sun-blocking agent. This melanin makes its way up through the epidermis, attached to other cells, and shields the DNA inside the nuclei of these cells from damaging UV radiation.
Now let’s find out a few facts about Melanomas.