A missense mutation in the 20S proteasome β2 subunit of Great Danes having harlequin coat patterning

Genomics. 2011 Apr;97(4):244-8. doi: 10.1016/j.ygeno.2011.01.003. Epub 2011 Jan 20.


Harlequin is a pigmentary trait of the domestic dog that is controlled by two autosomal loci: the melanosomal gene, SILV, and a modifier gene, harlequin (H), previously localized to chromosome 9. Heterozygosity for a retrotransposon insertion in SILV and a mutation in H causes a pattern of black patches on a white background. Homozygosity for H is embryonic lethal. Fine mapping of the harlequin locus revealed a 25 kb interval wherein all harlequin Great Danes are heterozygous for a common haplotype. This region contains one gene, PSMB7, which encodes the β2 catalytic subunit of the proteasome. Sequence analysis identified a coding variant in exon 2 that segregates with harlequin patterning. The substitution predicts the replacement of a highly conserved valine with a glycine. Described herein is the identification of a naturally-occurring mutation of the ubiquitin proteasome system that is associated with a discernable phenotype of dogs.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Breeding
  • Chromosome Mapping
  • Dogs / anatomy & histology*
  • Dogs / genetics*
  • Hair Color / genetics*
  • Haplotypes
  • Heterozygote
  • Homozygote
  • Molecular Sequence Data
  • Mutation, Missense*
  • Phenotype
  • Proteasome Endopeptidase Complex / genetics*
  • Retroelements / genetics
  • Sequence Analysis, DNA
  • gp100 Melanoma Antigen / genetics


  • Retroelements
  • gp100 Melanoma Antigen
  • Proteasome Endopeptidase Complex