page_title: Dark skin
section_title: Sub-Saharan Africa
hierarchical_section_title: Dark skin / Geographic distribution / Sub-Saharan Africa
caption_attribution_description: This is an image with the theme "Play" from: South Sudan
context_page_description: Dark skin is a human skin color that is rich in melanin pigments, especially eumelanin. People with very dark skin are often referred to as "black people", although this usage can be ambiguous in some countries where it is also used to specifically refer to different ethnic groups or populations.
  The evolution of dark skin is believed to have begun around 1.2 million years ago, in light-skinned early hominid species after they moved from the equatorial rainforest to the sunny savannas. In the heat of the savannas, better cooling mechanisms were required, which were achieved through the loss of body hair and development of more efficient perspiration. The loss of body hair led to the development of dark skin pigmentation, which acted as a mechanism of natural selection against folate depletion, and to a lesser extent, DNA damage. The primary factor contributing to the evolution of dark skin pigmentation was the breakdown of folate in reaction to ultraviolet radiation; the relationship between folate breakdown induced by ultraviolet radiation and reduced fitness as a failure of normal embryogenesis and spermatogenesis led to the selection of dark skin pigmentation.
context_section_description: Sub-Saharan Africa is the region in Africa situated south of the Sahara where a large number of dark-skinned populations live. Dark-skinned groups on the continent have the same receptor protein as Homo ergaster and Homo erectus had. According to scientific studies, populations in Africa also have the highest skin colour diversity. High levels of skin colour variation exists between different populations in Sub-Saharan Africa. These differences depend in part on general distance from the equator, illustrating the complex interactions of evolutionary forces which have contributed to the geographic distribution of skin color at any point of time.
  Due to frequently differing ancestry among dark-skinned populations, the presence of dark skin in general is not a reliable genetic marker, including among groups in Africa. For example, Wilson et al. (2001) found that most of their Ethiopian samples showed closer genetic affinities with lighter-skinned Armenians than with dark-skinned Bantu populations. Mohamoud (2006) likewise observed that their Somali samples were genetically more similar to Arab populations than to other African populations.
caption: Women from South Sudan
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