Characterisation of the melanocortin-1 receptor gene in alpaca and identification of possible markers associated with phenotypic variations in colour

Abstract

The aim of this study was to determine if any correlation exists between melanocortin-1 receptor (MC1R) polymorphisms and skin and fibre colour in alpacas. Primers capable of amplifying the entire alpaca MC1R gene were designed from a comparative alignment of Bos taurus and Mus musculus MC1R gene sequences. The complete MC1R gene of 41 alpacas exhibiting a range of fibre colours, and which were sourced from farms across Australia, was sequenced from PCR products. Twenty-one single nucleotide polymorphisms were identified within MC1R. Two of these polymorphisms (A82G and C901T) have the potential to reduce eumelanin production by disrupting the activity of MC1R. No agreement was observed between fibre colour alone and MC1R genotype in the 41 animals in this study. However, when the animals were assigned to groups based on the presence or absence of eumelanin in their fibre and skin, only animals that had at least one allele with the A82/C901 combination expressed eumelanin. We propose that A82/C901 is the wild-type dominant ‘E’ MC1R allele, while alpacas with either G82/T901 or G82/Y901 are homozygous for the recessive ‘e’ MC1R allele and are therefore unable to produce eumelanin.

Single nucleotide polymorphisms in the Melanocortin 1 Receptor gene are linked with lightness of fibre colour in Peruvian Alpaca (Vicugna pacos)

“…In previous studies, Feeley & Munyard (2009) reported that alpacas showing white fleece were heterozygotes for this polymorphism and that GG genotype animals presented a lack of eumelanin in the skin, in accordance with the results in our work. In previous studies, Feeley & Munyard (2009) reported that alpacas showing white fleece were heterozygotes for this polymorphism and that GG genotype animals presented a lack of eumelanin in the skin, in accordance with the results in our work.…”

“…Each animal of a colour group was chosen from a different herd. Eight of these 18 SNPs (c.82A>G, c.126T>C, c.258A>G, c.354T>C, c.376A>G, c.618G>A, c.901C>T and c.933G>A), all in the CDS, had been described previously (Powell et al 2008;Feeley & Munyard 2009), while 10 polymorphisms had never been described before. Five measurements were taken for each sample to obtain the average.…”

“…Polymorphisms c.82A>G (p.Thr28Ala) and c.901C>T (p.Arg301Cys) were hypothesized to be related to fibre colour by Powell et al (2008) and Feeley & Munyard (2009), while polymorphism c.865C>T was chosen in this study because it was found only in brown coloured animals and it produces an amino acid polar to nonpolar change in the protein. Polymorphisms c.82A>G (p.Thr28Ala) and c.901C>T (p.Arg301Cys) were hypothesized to be related to fibre colour by Powell et al (2008) and Feeley & Munyard (2009), while polymorphism c.865C>T was chosen in this study because it was found only in brown coloured animals and it produces an amino acid polar to nonpolar change in the protein.…”

Identification and characterization of microRNAs in white and brown alpaca skin

“…Studies of the melanocortin-1 receptor (MC1R) and agouti signaling protein (ASIP) genes in alpacas of different coat colors revealed several polymorphisms that may be predictive of coat color [14-18]. Powell et al reported that the M87V and S126G variants of MC1R may affect coat color with brown coat color animals showing homozygosity for the methionine and serine alleles [16].…”

Expression and tissue distribution of hepatocyte growth factor (HGF) and its receptor (c-Met) in alpacas (Vicugna pacos) skins associated with white and brown coat colors

“…Previous studies, including those we conducted, demonstrated that the three pigmentation critical enzymes, namely, tyrosinase (Tyr), tyrosinase-related protein 1 (Tyrp1), tyrosinaserelated protein 2 (DCT), and the critical factors, which include melanocortin-1 receptor protein (Mc1r), inducible nitric oxide synthase, micropthalmia-associated transcription factor (MITF), solute carrier family 7 member 11(Slc7a11), and ␤-catenin, were stimulators of melanogenesis in alpaca and agouti signaling proteins (Asip), miR-25 and miR-137 were inhibitors of melanogenesis in alpaca (Feeley and Munyard, 2009, Zhu, 2010, Chandramohan, 2013, Dong, 2012, Xue et al, 2014.…”