Red coat color in Holstein cattle is associated with a deletion in the MSHR gene

Abstract

In mammals, red/yellow and brown/black colorations are determined by the distribution of two pigments, phaeomelanin and eumelanin, respectively, the relative amounts of which are controlled primarily by two loci, extension and agouti. Dominant alleles at the extension locus increase brown/black pigmentation, while recessive alleles block eumelanin synthesis, thereby extending red/ yellow pigmentation within the hair follicle melanocyte. Robbins and associates (1993) have shown that the pigmentation phenotypes in mice controlled by the extension locus result from point mutations altering the function of the melanocyte-stimulating hormone receptor (MSHR). Johannson and colleagues (1994) demonstrated cosegregation of the chestnut (red) coat color in horses and polymorphisms at the MSHR locus. The black and red coat colors, respectively, in cattle are also controlled at the extension locus, the red color being due to a recessive allele (Searle 1968). The Holstein breed is stratified in red and black subpopulations. Gene flow from the black and white to the red and white subpopulation is through rare black carriers of the recessive red allele.To develop a direct test for determining the presence of the recessive allele causing red coat color in black Holstein cattle, we attempted to PCR amplify the bovine MSHR gene, assuming that the molecular basis of the bovine coat color phenotypes determined at the extension locus was similar to the one in horses and mice. The human (Chhajlani and Wikberg 1992) and mouse (Mountjoy et al. 1992) MSHR sequences were aligned to identify highly homologous regions suitable for designing primers based on the human sequences. In a first attempt we tried to amplify bovine DNA corresponding to a 544-bp segment of the human sequence using primer 1 and primer 2 (see Table 1). PCR was carried out in a reaction volume of 25 Ixl containing 100 ng of bovine or human genomic DNA, 10 mM Tris-HC1 pH 8.9, 50 mM KC1, 200 ~M of each deoxynucleotide, 0.4 ~M of each primer, and 2.5 U of Taq DNA polymerase (Boehringer Mannheim, Germany) in a thermal cycles (Hybaid Teddington, UK). MgC12 concentrations ranging from 1.5 to 3.0 mM with 0.5-mM increments were tested to optimize the PCR for specific amplification. After initial denaturation for 5 min at 95~ the PCR profile consisted of a denaturation step at 94~ for 30 s, an annealing step at 62~ for 30 s, and an elongation step at 72~ for 30 s for a total of 30 cycles, followed by a final extension of 7 min at 72~ The PCR product obtained when using bovine template DNA of a black Holstein animal consisted of two major bands between 500 and 600 bp, that is in the range of the human band at 544 bp. The two bovine bands were recovered from the agarose gel according to Heery and coworkers (1990) and subjected individually to another round of *Present address:

Born blonde: a recessive loss‐of‐function mutation in the melanocortin 1 receptor is associated with cream coat coloration inAntarctic fur seals

“…Many of these mutations that are not confined to transmembrane regions are either associated with a premature stop codon, as is the case for dogs and cattle (Joerg et al. 1996; Newton et al. 2000), or a frameshift mutation as in yellow recessive mice (Robbins et al.…”

Coat colours in the Massese sheep breed are associated with mutations in the agouti signalling protein (ASIP) and melanocortin 1 receptor (MC1R) genes

“…Gain-of-function and loss-of-function mutations of the MC1R gene determining dominant or partially dominant black/dark and recessive or partially recessive red/yellow/pale coat colour phenotypes, respectively, have been described in a large number of mammals including, for example, mice (Robbins et al, 1993), humans (Valverde et al, 1995) and several farm animals like cattle (Klungland et al, 1995;Joerg et al, 1996;Rouzaud et al, 2000), pigs (Kijas et al, 1998 and, horses (Marklund et al, 1996), dogs (Everts et al, 2000;Newton et al, 2000), cats (Eizirik et al, 2003;Peterschmitt et al, 2009), rabbits (Fontanesi et al, 2006) and goats (Fontanesi et al, 2009a). In sheep, classical genetic studies have identified two alleles at the Extension locus: the dominant black (E D ) allele caused by two missense mutations in the MC1R gene (p.M73K and p.D121N) and present in the Norwegian Dala, Corriedale, Damara, Black Merino, Black Castellana and Karakul breeds (Vå ge et al, 1999 andRoyo et al, 2008); and the wild type (E 1 ) allele widely distributed in most breeds (Searle, 1968;Sponenberg, 1997).…”

Melanocortin-1 receptor gene variants in four Chinese ethnic populations

“…Expressed on cutaneous melanocytes [3], MC1R is a seven transmembrane domain G protein-coupled receptor of 317 amino acids belonging to the melanocotin receptor subfamily and has high binding affinity for MSH and ACTH [8,9]. In addition, some other studies show that MC1R variants are associated with the coat colors in cattle [10], [11], fox [12], and horse [13].…”