Graf et al. (2007) examined the association between normal skin color variation in several populations and 3 different promoter polymorphisms in the MATP gene: -1721C-G (dbSNP rs13289), -1169G-A (dbSNP rs6867641), and a 3-bp duplication, -1174dupAAT. In Caucasian samples, ... Graf et al. (2007) examined the association between normal skin color variation in several populations and 3 different promoter polymorphisms in the MATP gene: -1721C-G (dbSNP rs13289), -1169G-A (dbSNP rs6867641), and a 3-bp duplication, -1174dupAAT. In Caucasian samples, -1721C-G and -1174dupAAT were in complete linkage disequilibrium. In Caucasians only, the -1721G, -1169A, and +dup alleles were significantly associated with olive skin color. Functional analysis in melanoma skin cells showed that this promoter haplotype decreased MATP transcription, suggesting a functional significance.