B-locus coat colour / Chocolate and Cinnamon (TYRP1-related) - Cat

What does this test analyse?

This DNA test analyses the TYRP1 gene at the feline B locus. This locus is also known as the brown locus and is important for Chocolate, Cinnamon, chestnut, light brown and related brown coat colours. The analysis detects the b allele for chocolate and the b^l allele for cinnamon.

What does it mean for coat colour?

The normal B allele supports full black pigment. The b allele reduces black pigment intensity and can produce a warm chocolate or chestnut brown colour. The b^l allele produces a lighter cinnamon or reddish-brown shade. The dominance order is B > b > b^l.

• B/B: no tested chocolate or cinnamon allele.
• B/b or B/b^l: carrier; the cat can pass on the corresponding allele.
• b/b: chocolate coat colour.
• b/b^l: chocolate coat colour and carrier of cinnamon.
• b^l/b^l: cinnamon coat colour.

Practical value of this test

The result helps identify chocolate, cinnamon and carrier status. This supports colour planning, mating choices and interpretation of kittens when other loci such as A locus, dilution, orange, colourpoint or tabby pattern also influence the visible coat.