Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, USA. savagesh@mail.nih.gov
BACKGROUND: The melanocortin 1 receptor gene (MC1R) is responsible for normal pigment variation in humans and is highly polymorphic with numerous population-specific alleles. Some MC1R variants have been associated with skin cancer risk. RESULTS: Allele frequency data were compiled on 55 single nucleotide polymorphisms from seven geographically distinct human populations (n = 2306 individuals). MC1R nucleotide diversity, pi, was much higher (10.1 x 10-4) than in other genes for all subjects. A large degree of population differentiation, determined by FST, was also present, particularly between Asia and all other populations, due to the p.R163Q (c.488 G>A) polymorphism. The least amount of differentiation was between the United States, Northern Europe, and Southern Europe. Tajima's D statistic suggested the presence of positive selection in individuals from Europe. CONCLUSION: This study further quantifies the degree of population-specific genetic variation and suggests that positive selection may be present in European populations in MC1R.