Human skin color diversity is highest in sub-Saharan African populations

Previous studies of genetic and craniometric traits have found higher levels of within-population diversity in sub-Saharan Africa compared to other geographic regions. This study examines regional differences in within-population diversity of human skin color. Published data on skin reflectance were collected for 98 male samples from eight geographic regions: sub-Saharan Africa, North Africa, Europe, West Asia, Southwest Asia, South Asia, Australasia, and the New World. Regional differences in local within-population diversity were examined using two measures of variability: the sample variance and the sample coefficient of variation. For both measures, the average level of within-population diversity is higher in sub-Saharan Africa than in other geographic regions. This difference persists even after adjusting for a correlation between within-population diversity and distance from the equator. Though affected by natural selection, skin color variation shows the same pattern of higher African diversity as found with other traits.