It is dominated by melanin, a pigmentation located in the base of the epidermis and produced by melanocytes. Skin color variation is one of the most striking examples of human phenotypic diversity. During migration, selective pressures in local environments (e.g., the cold climate, hypoxia, and endemic pathogens), together with random drift, have resulted in population-specific genetic variants, which further influenced variable phenotypes, such as lactose tolerance, height, immune system, and metabolic efficiency. Since modern humans ventured out of Africa ~100,000 years ago, they spread across continents into a variety of habitats, from tropical zones to the arctic, and from lowlands to highlands. Future work is needed to dissect the genetic architecture of skin color adaptation in numerous ethnic minority groups around the world, which remains relatively obscure compared with that of major continental groups, and to unravel the exact genetic basis of skin color adaptation. Previous studies generally indicated a complex genetic mechanism underlying the skin color variation, expanding our understanding of the role of population demographic history and natural selection in shaping genetic and phenotypic diversity in humans.

Finally, we provided a summary of the candidate loci associated with pigmentation, which could be a valuable reference for further evolutionary and medical studies.

We enumerated several cases of skin color adaptation in global modern humans and archaic hominins, and illustrated why, when, and how skin color adaptation occurred in different populations. In this review, we discuss what is currently known about the genetics of skin color variation. Impressive progress has been made recently to identify genes associated with skin color variation in a wide range of geographical and temporal populations. Understanding the genetic basis of adaptation of skin color in various populations has many implications in human evolution and medicine.

Skin color is a well-recognized adaptive trait and has been studied extensively in humans.

Skin map rf online