Melanocortin receptor 1 (MC1R) and agouti signaling protein (ASIP) are two major 
genes affecting coat color phenotypes in mammals, and inactivation mutations in 
the MC1R gene are responsible for red coat color in European pig breeds. 
Conversely, the gain-of-function ASIP mutations block MC1R signaling and lead to 
the production of red pheomelanin. Chinese Tibetan pigs have three types of coat 
color phenotypes, including brownish red, solid black and black with patches of 
brownish red and white. Herein, we investigated variations of the MC1R and ASIP 
genes in Tibetan pigs. The results showed that the brownish red Tibet pig had 
the dominant black MC1R allele (E(D1)). No loss-of-function mutation in MC1R 
responsible for red coat color in European breeds was observed in this breed. No 
causal mutation for the red coat color phenotype was found in the coding 
sequence of the ASIP gene. A novel missense mutation c.157G > A was firstly 
identified in exon 2 of ASIP, which was further genotyped in 285 pigs from five 
Chinese breeds and three Western breeds having different coat color phenotypes. 
Nearly all pigs were GG homozygotes. In conclusion, no functional variant 
responsible for brownish red coloration was found in the coding region of MC1R 
and ASIP in Tibetan pigs.