Mammalian pigmentation is guided by the melanocortin-1 receptor which depends on relative amount of pheomelanin and eumelanin. In the melanogenesis pathway the melanocortin-1-receptor (alpha melanocyte stimulating hormone receptor, MC1R) is responsible for the primary switch of pheomelanin for developing red to yellow pigment to eumelanin for black to brown pigment. In mammals, the difference in base colour are attributed due to mutations in the MC1R gene, also known as extension locus, historically codes for three alleles black (ED), red (e) and wild-type (E+) showed that there is existence of another allele E1. The extension alleles were assumed to be dominance in a descending order as ED> E+> e> E1. The wild-type allele (E+) having a 954 bp long coding sequence and encodes 317 Amino-acid in the full length MC1R gene. In the MC1R gene 150 bp upstream the ATG codon codes to the minimal gene promoter for the melanocyte-specific gene transcription. The MC1R protein, the amino acid similarity varied between 74.0% (mouse vs. dog) and 83.6% (cattle vs. dog). For MC1R, a comparison of nucleotide sequences similarity ranges between 75.1% (mouse vs. cattle) and 85.3% (pig vs. cattle).
Key words: MC1R, Allele, Receptor, Position, SNPs, Species