Abstract: Genetic and environmental factors are involved in the determination of skin pigmentation in humans. With the recent development of statistics and genetic tools in mapping complex traits in hu- mans, it becomes possible to utilize such methods in identifying genes involved in skin pigmentation. Furthermore, the use of new portable reflectance spectroscopy instruments such as the Photovolt ColorWalk colorimeter allows researchers to measure the skin reflectance from a large number of subjects with ease and accuracy for collecting phenotype data for genetic studies. In this report, we studied the skin reflectance of 372 Han Chinese and 274 Tibetan to establish background reflectance measurements of unexposed skin of the inner upper arm in these two populations using a new portable instrument (Photovolt ColorWalk). We investigated the effect of various factors such as age, gender, latitude, and ethnicity on skin reflectance. The normality of the distribution of skin reflectance was also investigated. Strategies for genetic studies of skin reflectance were suggested based on the results of this study.

Key words: Skin pigmentation; Quantitative traits; Genetics