There is a correlation between the geographic distribution of
UV radiation (UVR) and the distribution of skin pigmentation around the world. Areas that have higher amounts of UVR have darker-skinned populations, generally located nearer the
equator. Areas that are further away from the equator and generally closer to the poles have a lower concentration of UVR and contain lighter-skinned populations. This is the result of human evolution which contributed to variable melanin content in the skin to adapt to certain environments. Before the modern mass migration, it has been argued that the majority of dark-pigmented people lived within 20° of the equator. woman, Philippinesthe
Negritos are an indigenous people of Southeast Asia. Natives of
Buka and
Bougainville at the northern
Solomon Islands in Melanesia and the
Chopi people of
Mozambique in the southeast coast of Africa have darker skin than other surrounding populations. The native people of the
Autonomous Region of Bougainville have some of the darkest skin pigmentation in the world. Although these people are widely separated they share similar physical environments. In both regions, they experience very high UVR exposure from cloudless skies near the equator which is reflected from water or sand. Water reflects, depending on colour, about 10 to 30% of UVR that falls on it. People in these populations spend long hours fishing on the sea. Because it is impractical to wear extensive clothing in a watery environment, culture and technology does little to buffer UVR exposure. The skin takes a very large amount of ultraviolet radiation. These populations are probably near or at the maximum darkness that human skin can achieve.
Australia man with dark skin
Indigenous Australians, as with all other populations outside of Africa, are descendants of the Out-of-Africa wave. Genetic evidence has pointed out that the Indigenous peoples of Australia are genetically dissimilar to the dark-skinned populations of Africa and that they are more closely related to other non-African populations. The term black initially has been applied as a reference to the skin pigmentation of Indigenous Australians; today it has been embraced by Aboriginal activists as a term for shared
culture and identity, regardless of skin colour.
Melanesia boy from
Vanuatu,
Melanesia|alt=|left
Melanesia, a subregion of
Oceania, whose name means "black islands", have several islands that are inhabited by
people with dark skin pigmentation. The islands of Melanesia are located immediately north and northeast of Australia as well as east coast of Papua New Guinea. The western end of Melanesia from New Guinea through the Solomon Islands were first colonized by humans about 40,000 to 29,000 years ago. In the world,
blond hair is exceptionally rare outside Europe, North Africa and West Asia, especially among dark-skinned populations. However, Melanesians are one of the dark-skinned human populations known to have naturally occurring blond hair.
New Guinea ,
Papua New Guinea. People from Bougainville have some of the darkest skin tones among humans. The indigenous
Papuan people of
New Guinea have dark skin pigmentation and have inhabited the island for at least 40,000 years. Due to their similar phenotype and the location of New Guinea being in the migration route taken by
Indigenous Australians, it was generally believed that Papuans and Aboriginal Australians shared a common origin. However, a 1999 study failed to find clear indications of a single shared genetic origin between the two populations, suggesting multiple waves of migration into
Sahul with distinct ancestries.
Sub-Saharan Africa 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 colour at any point of time. Mohamoud (2006) likewise observed that their
Somali samples were genetically more similar to
Arab populations than to other African populations.
South Asia South Asia has some of the greatest skin colour diversity outside of Africa. Skin colour among South Indians is on average darker than North Indians. This is mainly because of the weather conditions in South Asia—higher UV indices are in the south. Several genetic surveys of South Asian populations in different regions have found a weak negative correlation between social status and skin darkness, represented by the melanin index. Tamils and Dravidian people descended from the original inhabitants of India. They have a dark skin tone because those original inhabitants were a dark skinned people who had migrated from out of Africa into India and other surrounding areas about 65,000 years ago. A study of caste populations in the
Gangetic Plain found an association between the proportion of dark skin and ranking in the caste hierarchy.
Dalits had, on average, the darkest skin. A pan-India study of Telugu and North Indian castes found a similar correlation between skin colour and caste association, linked to the absence of the rs1426654-A variant of the SLC245-A gene, but are also linked to mutations overriding these variants.
Americas couple from Colombia. Many other Indigenous peoples of tropical or subtropical areas of the Americas have dark skin. Relatively dark skin remains among the
Inuit and other Arctic populations. A combination of protein-heavy diets and summer snow reflection have been speculated as favouring the retention of pigmented skin. Most North American indigenous populations rank similar to African and Oceanian populations in regards to the presence of the allele
Ala111. Native South Americans and
Mesoamericans are also typically considered dark-skinned. File:Indigenous mother and daughter from Peru.png|An
Indigenous mother and daughter from the
Urus islands. File:Barretina taquile.JPG|An indigenous boy from
Peru. File:Amerindian man in his reed boat, on lake titicaca.png|An indigenous fisherman from
Lake Titicaca. File:Amerindian man from Peru.png|A man from
Bolivia. == Culture ==