Signature of balancing selection at the MC1R gene in Kunming dog populations

PLoS One. 2013;8(2):e55469. doi: 10.1371/journal.pone.0055469. Epub 2013 Feb 12.


Coat color in dog breeds is an excellent character for revealing the power of artificial selection, as it is extremely diverse and likely the result of recent domestication. Coat color is generated by melanocytes, which synthesize pheomelanin (a red or yellow pigment) or eumelanin (a black or brown pigment) through the pigment type-switching pathway, and is regulated by three genes in dogs: MC1R (melanocortin receptor 1), CBD103 (β-defensin 103), and ASIP (agouti-signaling protein precursor). The genotypes of these three gene loci in dog breeds are associated with coat color pattern. Here, we resequenced these three gene loci in two Kunming dog populations and analyzed these sequences using population genetic approaches to identify evolutionary patterns that have occurred at these loci during the recent domestication and breeding of the Kunming dog. The analysis showed that MC1R undergoes balancing selection in both Kunming dog populations, and that the Fst value for MC1R indicates significant genetic differentiation across the two populations. In contrast, similar results were not observed for CBD103 or ASIP. These results suggest that high heterozygosity and allelic differences at the MC1R locus may explain both the mixed color coat, of yellow and black, and the difference in coat colors in both Kunming dog populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agouti Signaling Protein / genetics
  • Animals
  • Breeding*
  • Dogs / anatomy & histology
  • Dogs / genetics*
  • Genetic Loci / genetics
  • Hair / anatomy & histology
  • Haplotypes / genetics
  • Pigmentation / genetics
  • Polymorphism, Single Nucleotide
  • Receptor, Melanocortin, Type 1 / genetics*
  • Species Specificity
  • beta-Defensins / genetics


  • Agouti Signaling Protein
  • Receptor, Melanocortin, Type 1
  • beta-Defensins

Grant support

This work was supported by grants from the National Basic Research Program of China (973 Program, 2013CB835200), National Natural Science Foundation of China (91231108), Chinese Academy of Sciences, and Bureau of Science and Technology of Yunnan Province. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.