Skin Pigmentation Variation

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Skin pigmentation in modern humans is an adaptation to ultraviolet radiation. The most darkly pigmented skin is found among people living at or near the equator; the most lightly pigmented skin is found among people living above 45N latitude. The primary pigment in human skin is melanin, mostly in the form of the very dark brown eumelanin. Yellow-red pheomelanin is present in human skin to varying degrees, and is most obvious as the pigment causing freckles in people with very lightly pigmented skin. Eumelanin is a superior natural sunscreen with abilities to absorb wavelengths of visible and ultraviolet radiation. Darkly pigmented skin with high concentrations of eumelanin confers protection against high levels of both ultraviolet A (UVA=315-345 nm) and ultraviolet B (UVB=280-315 nm) radiation. Ultraviolet radiation is mostly harmful to humans because it damages DNA and breaks down folate, a B vitamin necessary for DNA synthesis and cell division.

The earliest members of Homo sapiens living in eastern and northeastern Africa were darkly pigmented, and genetic evidence indicates that variation in one of the primary genes controlling eumelanin production, the melanocortin 1 receptor (MC1R), was lost as the result of a selective sweep about 1.2 myr. Human dispersal into higher latitudes with lower levels of UVR was associated with positive selection for depigmentation. Although UVR is mostly harmful, UVB (optimally at 297 nm) initiates the production of vitamin D in the skin from a cholesterol-like precursor. Vitamin D is required for absorption of calcium and the growth and maintenance of a healthy skeleton; it is also important for normal development and functioning of the immune system and brain. Positive selection for depigmentation was driven by the importance of maintaining vitamin D photosynthesis in the skin under conditions of reduced UVB at higher latitudes. Evolution of depigmented skin occurred at least twice in Homo sapiens, in both the ancestors of modern northern Europeans and eastern Asians.


  1. Rapid evolution of a skin-lightening allele in southern African KhoeSan, Lin, Meng, Siford Rebecca L., Martin Alicia R., Nakagome Shigeki, Möller Marlo, Hoal Eileen G., Bustamante Carlos D., Gignoux Christopher R., and Henn Brenna M. , Proceedings of the National Academy of Sciences, 2018/12/06, p.201801948, (2018)
  2. Loci associated with skin pigmentation identified in African populations, Crawford, Nicholas G., Kelly Derek E., Hansen Matthew E. B., Beltrame Marcia H., Fan Shaohua, Bowman Shanna L., Jewett Ethan, Ranciaro Alessia, Thompson Simon, Lo Yancy, et al. , Science, 2017/10/12, (2017)
  3. Genome flux and stasis in a five millennium transect of European prehistory., Gamba, Cristina, Jones Eppie R., Teasdale Matthew D., McLaughlin Russell L., Gonzalez-Fortes Gloria, Mattiangeli Valeria, Domboróczki László, Kővári Ivett, Pap Ildikó, Anders Alexandra, et al. , Nat Commun, 2014, Volume 5, p.5257, (2014)
  4. Genetic evidence for the convergent evolution of light skin in Europeans and East Asians., Norton, Heather L., Kittles Rick A., Parra Esteban, McKeigue Paul, Mao Xianyun, Cheng Keith, Canfield Victor A., Bradley Daniel G., McEvoy Brian, and Shriver Mark D. , Mol Biol Evol, 2007 Mar, Volume 24, Issue 3, p.710-22, (2007)
  5. SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans., Lamason, Rebecca L., Mohideen Manzoor-Ali P. K., Mest Jason R., Wong Andrew C., Norton Heather L., Aros Michele C., Jurynec Michael J., Mao Xianyun, Humphreville Vanessa R., Humbert Jasper E., et al. , Science, 2005 Dec 16, Volume 310, Issue 5755, p.1782-6, (2005)
  6. Worldwide polymorphism at the MC1R locus and normal pigmentation variation in humans., Makova, Kateryna, and Norton Heather , Peptides, 2005 Oct, Volume 26, Issue 10, p.1901-8, (2005)
  7. Genetic variation at the MCIR Locus and the time since loss of human body hair, Rogers, Alan R., Iltis David, and Wooding Stephen , Current Anthropology, Volume 45, Issue 1, p.105-124, (2004)
  8. The IFPCS presidential lecture: a chemist's view of melanogenesis., Ito, Shosuke , Pigment Cell Res, 2003 Jun, Volume 16, Issue 3, p.230-6, (2003)
  9. The evolution of human skin coloration., Jablonski, N G., and Chaplin G , J Hum Evol, 2000 Jul, Volume 39, Issue 1, p.57-106, (2000)
  10. Pheomelanin as well as eumelanin is present in human epidermis., Thody, A J., Higgins E M., Wakamatsu K, Ito S, Burchill S A., and Marks J M. , J Invest Dermatol, 1991 Aug, Volume 97, Issue 2, p.340-4, (1991)