MC1R gene polymorphisms analysis associated with human pigmentation phenotypes on the brazilian population

Abstract

Among the known genes infl uencing eye, skin and hair normal pigmentation variation, the MC1R (melanocortin 1-receptor) gene is the best characterized so far. The activity of MC1R occurs due the production of a transmembrane protein in melanocytes, responsible for regulating the production of melanin. It is known that the performance of MC1R determines the ratio of eumelanin (brown /black color) and pheomelanin (yellow/ red) present in melanocytes. This study aims to analyze known SNPs of the MC1R gene in order to evaluate the infl uence of this gene diversity on features like freckles and pigmentation variation of eyes, skin and hair in humans. We analyzed 29 known SNPs in the coding region of MC1R gene in 296 individuals from the region of Ribeirão Preto, Brazil. DNA extraction was performed using the salting-out technique. The MC1R gene coding region (951pb) was amplifi ed in a single PCR reaction, which was sequenced on a ABI PRISM-310 genetic analyzer by capillary electrophoresis, using the same primers used for amplifi cation. Of the 29 SNPs evaluated, only 22 showed variation in the samples studied, half of them showing to be associated with pigmentation characteristics. We observed a set of SNPs clearly associated to pheomelanin (+1645 A, +1831 T,+1858 T e +2260 C), while others related to eumelanin occurrence (+1558 G, +2322 G, +2346 A). Our study shows signifi cant associations between individual SNPs and eyes, hair and skin pigmentation. The results presented here confi rm that this gene also plays a relevant role in the pigmentation variation in the Brazilian population.