Research has indicated that the evolution of black skin during the earliest times of our human history may have been to avoid cancer cells from spreading. Scientists who did the research believe that the appearance of black skin over a million years ago was a method of preventing Africans from dying of skin cancer.
This change happened when ancient humans eventually shed most of the hair on their bodies and went out into the hot African climate. Before this point, there would have been pale skin underneath their hair, similar to chimpanzees today.
The evidence related to the study shows that the sun’s rays could have placed selection pressure on those early humans who lived about 1.5 million years ago. Those individuals who had darker skins would have been safe from the prospect of dying at a young age from skin cancer. The protective genes they possessed were able to be passed on to their future generations. This particular theory has not been accepted prior to this study as it was believed that young people rarely died at a young enough age to affect the reproduction genes.
This study has taken into account the effects of the sun’s rays on those who suffer with albinism. This is a condition that indicates a lack of melanin production which is responsible for skin, eye and hair colouring. It has shown that Albinos from African countries with high levels of ultraviolet radiation from the sun’s rays generally develop skin cancer which causes death at a young age.
The Institute of Cancer Research has stated that Charles Darwin did not think that skin colour was of any adaptive value, and there have been others who have dismissed cancer as a force during evolution. However, the clinical data that is available on Albinos, particularly those in Africa, have provided scientists with a very good argument that human evolution and the development of darker skins has a link to cancer.
According to this research, there is an indication that a minimum of 80% of Albinos from countries such as Tanzania and Nigeria succumb to the effects of skin cancer before they reach the age of 30. This also applies to countries such as Panama that experience all-year sunshine.
It is believed that in addition to offering protection from cancer, black skins may prevent sweat gland damage and it preserves folate, which is essential for healthy development of foetuses.
Image credit: David Robert Bliwas