A first genotyping assay of French cattle breeds based on a new allele of the extension gene encoding the melanocortin-1 receptor (Mc1r)

Abstract

The seven transmembrane domain melanocortin-1 receptor (Mc1r) encoded by the coat color extension gene (E) plays a key role in the signaling pathway of melanin synthesis. Upon the binding of agonist (melanocortin hormone, α-MSH) or antagonist (Agouti protein) ligands, the melanosomal synthesis of eumelanin and/or phaeomelanin pigments is stimulated or inhibited, respectively. Different alleles of the extension gene were cloned from unrelated animals belonging to French cattle breeds and sequenced. The wild type E allele was mainly present in Normande cattle, the dominant ED allele in animals with black color (i.e. Holstein), whereas the recessive e allele was identified in homozygous animals exhibiting a more or less strong red coat color (Blonde d'Aquitaine, Charolaise, Limousine and Salers). A new allele, named E1, was found in either homozygous (E1/E1) or heterozygous (E1/E) individuals in Aubrac and Gasconne breeds. This allele displayed a 4 amino acid duplication (12 nucleotides) located within the third cytoplasmic loop of the receptor, a region known to interact with G proteins. A first genotyping assay of the main French cattle breeds is described based on these four extension alleles.

Isolation and characteristics of the melanocortin 1 receptor gene (MC1R) in the Chinese yakow (Bos grunniens×Bos taurus)

“…However, red coat colour in Holstein cattle was associated with the e locus (Joerg et al, 1996). Red breeds of cattle in France such as Blonde d'Aquitaine, Charolais, Limousine and Salers were shown to be exclusively composed of homozygous e/e animals (Rouzaud et al, 2000).…”

Missense and nonsense mutations in melanocortin 1 receptor (MC1R) gene of different goat breeds: association with red and black coat colour phenotypes but with unexpected evidences

“…Primers for caprine MC1R amplification and sequencing (Additional file 1) were designed with Primer 3 (Whitehead Institute for Biomedical Research, Cambridge, MA) from the published goat DNA sequence that only accomplish the coding region (GenBank accession number: Y13958) [47] and from the bovine MC1R complete gene sequence that includes 5'- and 3'-untranslated and flanking regions (GenBank accession number: AF445641) [9]. Sequences were obtained from 48 random goats across six breeds (Girgentana, 10; Maltese, 10; Derivata di Siria, 10; Murciano-Granadina, 6; Camosciata delle Alpi, 6; Saanen, 6).…”

“…Mutations of the MC1R gene affecting coat colour have been described in several mammals, such as mice [2], humans [5], guinea pigs [6], cattle [7-9], pigs [10], horses [11], sheep [12], dogs [13,14], foxes [15], bears [16], felids [17], rabbits [18], and pocket mice [19], in which gain of function mutations produce black/dark coat colour, whereas loss of function mutations cause red/yellow or white coat colour.…”

The role of MC1R gene in buffalo coat color

“…There are 4 major E-alleles found in cattle regulating different pigmentation situations. The coat color in animals carrying wild type E + alleles is dependent on other loci regulating the pigmentation [13], while E D , e, and E L alleles give black, red (e/e homozygote), and fawn to brown or grey coat colours, respectively [11,13,14]. However, in Yak (Bos grunniens), another member of the same bovidae family, the MC1R was reported to have no association with Yak coat color [15].…”