A mutation in the Brown gene (tyrosinase-related protein-1, TYRP1) results in the Cinnamon coat colour.
The bI allele produces a light brown or cinnamon colouration. The mutation is recessive, hence two copies of the bI allele are required for cinnamon colouration.
|Cinnamon (bI/bI)||Has two copies of the Cinnamon allele (bI/bI)
Cat is Cinnamon
|Carrier of Cinnamon (B/bI or b/bI)||Has one copy of the Cinnamon allele (B/bI or b/bI)
Full colour or possibly Chocolate if the cat also carries Chocolate
|Does not carry Cinnamon (B/B, B/b or b/b)||Has no copies of the Cinnamon allele (B/B, B/b or b/b)
Full colour or possibly Chocolate
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|