MC1R RECEPTOR

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Recommended: The evolution of human skin color Annie Prud'homme- Genereux

Anthropologists and geographers have exposed the relationship between skin color and spatial arrangement (Jablonski and Chaplin 2002). Individuals with darker skin are found closer to the equator compared to lighter skinned populations (Jablonski and Chaplin 2002). It was originally thought that having darker skin was associated with an evolutionary defense mechanism concerning the protection from skin cancer (Jablonski and Chaplin 2002). However, further investigations suggest that skin pigmentation is dependent upon natural selection in charge of regulating UV radiation (Jablonski and Chaplin 2002).
The evolution of early humans was necessary to preserve an optimal body temperature and thus prevent overheating (Jablonski and Chaplin 2002). The body began adapting by increasing the number of sweats glands and decreasing hair production establishing a cooler body temperature (Jablonski and Chaplin 2002). As humans started to have bare skin, melanin pigments formed and created a barrier against the damaging cancerous UV rays (Jablonski and Chaplin 2002). Melanin absorbs the energy of UV rays and counterbalances UV damage by offsetting free radicals (Jablonski and Chaplin 2002).
Our earliest ancestors, called Homo sapiens, evolved about 120,000 years ago within Africa (Jablonski and Chaplin 2002). Homo sapiens had dark skin pigments thus high levels of melanin, which prevented most of the ultraviolet rays from penetrating their skin (Jablonski and Chaplin 2002). The long term UV radiation exposure can cause DNA damage and lead to cancer (Jablonski and Chaplin 2002). Therefore, dark pigments were an evolutionary adaptation to the high temperatures from the equator (Jablonski and Chaplin 2002). Moreover, the darker pigments prote...

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...n heritage.

Works Cited

Jablonski, N. G. 2002. "The Naked Truth." Scientific American 42-49. Print.

Lin, J. Y., and D.E. Fisher. 2007."Melanocyte Biology and Skin Pigmentation." Nature 445.7130: 843-50. Print.

Mas, J. S., C. O. Sanchez, G. Ghanem, J. Haycock, J. A. Lozano Teruel, J. C. Garcia-Borron, and C. Jimenez-Cervantes. 2002. "Loss-of-function Variants of the Human Melanocortin-1 Receptor Gene in Melanoma Cells Define Structural Determinants of Receptor Function." European Journal of Biochemistry 269.24 : 6133-141. Print.
Rees, J.L. “The genetics of skin and hair pigmentation in man.” The University of Edinburgh :UK 842-843 (2003)

Valverde, P., E. Healy, I. Jackson, J. L. Rees, and A. J. Thody. 1995. "Variants of the Melanocyte–stimulating Hormone Receptor Gene Are Associated with Red Hair and Fair Skin in Humans." Nature Genetics 11.3 : 328-30. Print.

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