A mutation in the Brown gene (tyrosinase-related protein-1, TYRP1) results in the Chocolate coat colour.
The B allele is wild-type and produces a normal colouration, the b allele produces a chocolate colouration. The mutation is recessive, hence two copies of the b allele are required for chocolate colouration.
|Chocolate (b/b)||Has two copies of the Chocolate allele (b/b)
Cat is Chocolate
|Carrier of Chocolate (B/b)||Has one copy of the Chocolate allele (B/b)
Full colour or possibly Chocolate if the cat also carries Cinnamon
|Does not carry Chocolate (B/B, B/bl or bl/bl)||Has no copies of the Chocolate allele (B/B, B/bl or bl/bl)
Full colour or possibly Cinnamon
The results must be Chocolate (b/b) and Dilute (d/d) for the Ragdoll to be Lilac.
The results must be Chocolate (b/b) and Dilute (d/d) or Chocolate carrying Cinnamon (b/bI) and Dilute (d/d) for the British Shorthair to be Lilac.
Black is diluted to Blue
Chocolate is diluted to Lilac
Cinnamon is diluted to Fawn
Red is diluted to Cream
|BB or Bb or BbI||DD or Dd||Black/Brown|
|BB or Bb or BbI||dd||Blue|
|bb or bbI||DD or Dd||Chocolate|
|bb or bbI||dd||Lilac|
|bIbI||DD or Dd||Cinnamon|