Melanocortin 4 receptor (MC4R)

Abstract

The melanocortin 1 receptor (MC1R) plays a central role in regulation of eumelanin(black/brown) and phaeomelanin (red / yellow) synthesis within the mammalian melanocyte and encoded by the classical Extension (E) coat color locus. The objectives of this study were carried out to observe the genotype frequencies of MC1R in 1,044 samples of imported beef and eight different cattle breeds including Hanwoo, Holstein, Angus, Brown-Swiss, Charolais, Limousin, Simmental and Hereford. The primers for the amplification of bovine MC1R gene were designed based on a bovine MC1R gene sequence (GenBank accession no. Y19103). A size of 350 by was amplified by polymerase chain reaction(PCR), digested with each or together of two different restriction enzyme, BsrFI and MspAII, and electrophoresed in 2.5% or 4% Metaphore agarose gel for determination of genotypes. One thousand and forty four samples including eight different cattle breeds and imported beef were determinated their genotypes by PCR-RFLP. Genotype frequencies of Hanwoo were 0.10 in E e and 0.90 in ee. Allele E^D was shown in all of Holstein and Angus breeds tested which have black coat color phenotypes. However, genotype frequencies of Limousin and Simmental breeds were 0.21 and 0.07 in E^DE^D, 0.00 and 0.03 in E^De^+ , 0.38 and 0.35 in E^De, respectively. These results of this study suggest that alleles of the bovine MC1R gene are associated strongly with coat color except for Simmental and Limousin breeds with dark brown, light yellow or mosaic coat color of red and brown. Therefore, it needs to be studied on relationship between A and E loci and coat color phenotypes. Furthermore, genotypes of the bovine MC1R gene can be used as a DNA marker for distinguishing. beef between Hanwoo and Holstein and Angus having black coat color phenotype.