Test Detail

Genetic panel that analyses the six classic coat colour loci of the dog: E (extension, MC1R), A (agouti, ASIP), B (brown, TYRP1), K (dominant black, CBD103), D (dilution, MLPH) and S (white spotting, MITF). It allows the coat colour and pattern to be predicted and transmission to be estimated. Complementary to, not a substitute for, clinical examination.

Applicable breed: all dog breeds. Frequencies: limited data; allelic distribution varies greatly between breeds.

• E (MC1R): controls eumelanin production; the recessive e alleles produce red/yellow coats.
• A (ASIP): distributes pigment (fawn/sable, agouti, saddle tan, black-and-tan, recessive black).
• B (TYRP1): dilutes black to brown (liver/chocolate).
• K (CBD103): K^B produces dominant black; k^br brindle; k^y allows expression of the A locus.
• D (MLPH): dilutes pigment (blue, grey, lilac).
• S (MITF): determines white spotting (Irish, piebald, extreme white).

The E, A, B, K, D and S loci were described over decades; their molecular basis was resolved between 2000 and 2021 (MC1R, ASIP, TYRP1, CBD103, MLPH and MITF). The allelic nomenclatures have been recently revised, especially at the E and A loci.

• Interpret the panel in an integrated way, not locus by locus: the final colour depends on epistasis.
• In breeds with fixed K^B, the A locus is not expressed; do not select for A without knowing K.
• Avoid mating two carriers of recessive dilution (D) if the diluted phenotype is not sought.
• In S spotting, the accumulation of alleles can increase white and, in some breeds, be associated with deafness.
• A negative result does not rule out alleles not included in the panel.

Additional alleles and nomenclatures under revision exist (e.g. eH, ASIP haplotypes). The test should be interpreted together with the phenotype; in certain breeds there may be alleles not covered. MLPH dilution may be associated with colour dilution alopecia (CDA) in some breeds.

1. Newton 2000, Melanocortin 1 receptor variation in the domestic dog (E) (PMID 10602988); OMIA:001199-9615.
2. Everts 2000, Premature stop codon in MC1R in yellow retrievers (E) (PMID 10895310); OMIA:001199-9615.
3. Kerns 2004, Characterization of the dog Agouti gene and a nonagouti mutation (A) (PMID 15520882); OMIA:000201-9615.
4. Bannasch 2021, Dog colour patterns explained by modular promoters of ancient canid origin (A) (PMID 34385618); OMIA:000201-9615.
5. Schmutz 2002, TYRP1 and MC1R genotypes and their effects on coat color (B) (PMID 12140685); OMIA:001249-9615.
6. Candille 2007, A beta-defensin mutation causes black coat color in domestic dogs (K) (PMID 17947548); OMIA:001416-9615.
7. Drogemuller 2007, Noncoding MLPH SNP at the splice donor of exon 1 and coat color dilution (D) (PMID 17519392); OMIA:000031-9615.
8. Karlsson 2007, Efficient mapping of mendelian traits in dogs and MITF white spotting (S) (PMID 17906626); OMIA:000214-9615.
9. Anderson 2020, Comprehensive genetic testing and ancient MC1R mutation (E) (PMID 33292722); OMIA:001199-9615.