shared genetic origin between the two populations, suggesting multiple waves of migration into sahul with distinct ancestries. sub-saharan africa women from south sudan 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 color diversity. high levels of skin color 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 darker-skinned bantu populations. mohamoud (2006) likewise observed that their somali samples were genetically more similar to arab populations than to other african populations. south asia fisherman from chennai, tamil nadu in southern india. south asia has some of the greatest skin color diversity outside of africa. skin color 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. 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 color 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 a dark-skinned wayuu 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. earliest european colonial descriptions of north american populations include terms such as "brown", "tawny" or "olive", though some populations were also described as "light-skinned". 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. high ultraviolet radiation levels occur throughout the andes region of peru, bolivia, chile, and argentina. indigenous mother and daughter from the urus islands. indigenous man from bolivia. indigenous fisherman from lake titicaca. culture the preference or disfavour for darker skin has varied depending on geographical area and time. today, darker skin is viewed as fashionable and as a sign of well-being in some societies. this resulted in the development of tanning industry in several countries. however, in some countries, dark skin is not seen as highly desirable or indicative of higher class, especially among women.