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Feline chocolate colour (multi-breed)

Dermatological · Cat

The chocolate (brown) colour of the cat is a pigmentation trait produced by variants of the TYRP1 gene. Cats with two copies of the b allele show a chocolate (chestnut) coat, whereas the b^l allele produces the light brown or cinnamon colour. It is a visible trait and not a disease, and it is inherited in an autosomal recessive manner with respect to the B allele (wild-type black).
Inheritance patternAutosomal recessive (allelic series B > b > b^l): chocolate in bb or bb^l; cinnamon in b^lb^l
Gene / MutationTYRP1 b: c.1261+5G>A (splice donor site of intron 6), linked to c.8C>G p.(A3G); b^l allele: c.298C>T p.(R100*); allelic series B > b > b^l (OMIA001249)
PenetranceCoat colour is expressed almost completely in homozygous and compound genotypes (bb, bb^l, b^lb^l); the final tone depends on other pigmentation loci (e.g. dilution, tabby).
Sample typesangre con EDTA 1mL
Codeqaup
Turnaround time10 days
Price57,53 €
Breedstodas las razas

Incidence

Present in numerous feline breeds and in mixed-breed cats (multi-breed trait). There are no consolidated allele frequencies.

Clinical signs

It is not a disease: it is a coat colour trait. It produces no clinical signs and does not affect the animal's health.

History

The molecular basis of the feline brown colour was described in 2005 by two independent groups: Lyons et al. and Schmidt-Küntzel et al. identified in TYRP1 a splice donor site mutation of intron 6 associated with the chocolate b allele, and a nonsense mutation at codon 100 (p.R100*) associated with the cinnamon b^l allele. Both alleles form the series B > b > b^l.

Breeder management

- It is not a disease: no testing is required for health reasons, but the test allows predicting the colour of the offspring.\n- Two chocolate cats (bb) will only produce chocolate offspring.\n- A black carrier cat (Bb) can transmit the allele to half of its offspring.\n- The test distinguishes the b allele (chocolate) from the b^l allele (cinnamon).

Specialist notes

The chocolate colour coexists with other pigmentation variants (dilution, spotting, tabby, etc.) that modify the final appearance. Do not confuse the TYRP1 b allele with the feline blood group B locus or with "brown" in other species. In cats, the cinnamon b^l allele is recessive with respect to b.

References

1. Lyons LA, Foe IT, Rah HC, Grahn RA. Chocolate coated cats: TYRP1 mutations for brown color in domestic cats. Mamm Genome 2005. PMID:16104383.
2. Schmidt-Küntzel A, Eizirik E, O'Brien SJ, Menotti-Raymond M. Tyrosinase and tyrosinase related protein 1 alleles specify domestic cat coat color phenotypes of the albino and brown loci. J Hered 2005. PMID:15858157.
3. OMIA:001249-9685 Coat colour, brown, TYRP1-related (Felis catus).
Price: 57,53 € · Turnaround time: 10 days

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