Allelic variation of melanocortin-1 receptor locus in Saudi indigenous sheep exhibiting different color coats

Abstract

ObjectiveThis study was designed to characterize the DNA polymorphisms of the melanocortin-1 receptor (MC1R) gene in indigenous Saudi Arabian sheep breeds exhibiting different color coats, along with individuals of the Sawaknee breed, an exotic sheep imported from Sudan.MethodsThe complete coding region of MC1R gene including parts of 3′ and 5′ untranslated regions was amplified and sequenced from three the indigenous Saudi sheep; Najdi (generally black, n = 41), Naeimi (generally white with brown faces, n = 36) and Herri (generally white, n = 18), in addition to 13 Sawaknee sheep.ResultsFive single nucleotide polymorphisms (SNPs) were detected in the MC1R gene: two led to nonsynonymous mutations (c.218 T>A, p.73 Met>Lys and c.361 G>A, p.121 Asp>Asn) and three led to synonymous mutations (c.429 C>T, p.143 Tyr>Tyr; c.600 T>G, p.200 Leu>Leu, and c.735 C>T, p.245 Ile>Ile). Based on these five SNPs, eight haplotypes representing MC1R Ed and E+ alleles were identified among the studied sheep breeds. The most common haplotype (H3) of the dominant Ed allele was associated with either black or brown coat color in Najdi and Sawaknee sheep, respectively. Two other haplotypes (H6 and H7) of Ed allele, with only the nonsynonymous mutation A218T, were detected for the first time in Saudi indigenous sheep.ConclusionIn addition to investigating the MC1R allelic variation in Saudi indigenous sheep populations, the present study supports the assumption that the two independent nonsynonymous Met73Lys and Asp121Asn mutations in MC1R gene are associated with black or red coat colors in sheep breeds.

Comparative transcriptome and histological analyses provide insights into the skin pigmentation in Minxian black fur sheep (Ovis aries)

“…Pigmentation, UV responses, and melanoma risk are regulated by the MC1R gene ( Wolf Horrell, Boulanger & D’Orazio, 2016 ). Research has shown that the MC1R allelic variations are associated with black or red coat colors in Saudi sheep populations ( Mahmoud et al, 2017 ), which provides the theoretical basis for selecting MC1R as the candidate gene in our study. Research has suggested that oculocutaneous albinism type 2 may be caused by mutations in the OCA2 (pink-eye dilution homolog) gene, resulting in diluted phenotypes ( Reissmann & Ludwig, 2013 ) and sequence variations in OCA2 showed additional association with eye color ( Mengel-From et al, 2010 ).…”

Detection of Snps in the Melanocortin 1-Receptor (MC1R) and Its Association with Shank Color Trait in Hs Chicken

“…A 2-bp insertion in MC1R gene leads to recessive white coat pigmentation in Bama miniature pigs (Jia et al, 2017). The two independent and nonsynonymous Met73Lys and Asp121Asn mutations in the MC1R gene are associated with black or red coat colors in Saudi indigenous sheep populations (Mahmoud et al, 2017). The single nucleotide polymorphism (901C/T) found in the coding region of MC1R was linked to the white coat color in in the Arabian camel (Almathen et al, 2018).…”

Transcriptome profiling analysis reveals key genes of different coat color in sheep skin

“…In Xinjiang, the local sheep have four coat colors. Previous studies have identified two alleles at the extension locus in sheep: the dominant black allele (E D ), which accounts for the black pigmentation of colored breeds and the wild type allele (E + ), which is widely distributed in most breeds (Våge et al, 1999; Yang et al, 2013; Mahmoud et al, 2017) and has also been observed in 13 breeds of sheep in China (Yang et al, 2013). Significant associations between these alleles and coat color were found within or near the ASIP , ITCH , AHCY and RALY genes on chromosome 13 for black and brown coat colors and the KIT and PDGFRA genes on chromosome six for white coat color using genome-wide association studies in Markhoz (Nazari-Ghadikolaei et al, 2018).…”