A Locus (Agouti) - cats

Agouti is a general marking used for origin colour of many animal kinds, e.g. mice, brown rats, guinea pigs, or rabbits. The gene responsible for the regulation of the dark pigment distribution (eumelanin) is called ASIP (Agouti Signalling Protein). Agouti allele is marked A, and this allele is dominant. Agouti colouring appears as changing of dark and light strips of individual animal hair (this is called ticking). Allele marked a-non agouti is a source of uniform colour of animal fur. Related to the uniform cat coat colour, 2 bp deletion in exon of ASIP gene was found (Eizirik et al. 2010). This mutation is inherited recessively. The fur of a/a individual is coloured uniformly and any possible drawing is not visible.

Genotypes:

• A/A  - agouti  colouring -  hair with ticking
• A/a  - agouti colouring - individuals give the non-agouti allele to their descendants
• a/a  - uniform coat colour

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Genotypes A/A or A/a enable the manifestation of the drawing on cat's fur. T locus (allelic series T^a ˃T^s˃T^m˃ t^b) is responsible for the possible presence of drawing. The A locus test does not provide the information regarding the type of coat drawing. With the cats, we recognize the following types of fur drawings corresponding to the mentioned T-alleles:

• ticked tabby - cat's hair is striped , the coat is darker along backbone (eel strip)

• spotted tabby

• mackerel tabby

• blocked tabby - oval spots or thicker spots than with Mackerel tabby

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References:

Eizirik, E., N. Yuhki, W. E. Johnson, M. Menotti-Raymond, S. S. Hannah et al., 2003 Molecular genetics and evolution of melanism in the cat family. Curr. Biol. 13: 1-20.

Lyons, L. A., S. J. Bailey, K. C. Baysac, G.Byrns, C. A. Erdman et al., 2006 The Tabby cat locus maps to feline chromosome B1. Anim. Genet. 37: 383-386.