Orange Tonkinese

Orange Series Tonkinese

When mating the basic colours (Brown, Blue, Chocolate, Cinnamon, Lilac, Fawn and Caramel) it doesn't matter which parent is a particular colour, but it does matter in a mating for the Orange series colours (Red, Cream, Apricot or Tortoiseshell). For example, to produce an Orange male kitten the dam must be Orange or Tortie, to produce an Orange female kitten both parents must be Orange series. So, in order to breed for the Orange series colours you need to understand a little about the behaviour of the Orange making gene (O-).

Adhuish Atlas, Cream Male TCR - © Linda Vousden

Adeeish Macrose Fantasy, Blue Tortoiseshell BCR © Linda Vousden

1) The Orange making gene is dominant: If the Orange gene (OO or Oo) is inherited from its parents the cat will be one of the orange series colours. If only the non-Orange version of the gene (oo) is inherited then the cat will be non-orange (e.g Brown, blue chocolate etc).

2) The Orange gene is sex-linked: Cats have 19 pairs chromosomes that are in identical pairs except for one - the sex chromosome pair. The female sex chromosome pair is XX, but the male chromosome pair is XY. The Orange gene can only be inherited if it is present with the X chromosome.

The following variations occur, the asterisk * indicates the presence of the Orange gene, OO or Oo :-

Males:
X Y = Non-Orange males
X* Y = Orange males

Females:
X X = Non-Orange females
X* X* = Orange females
X* X = Tortoiseshell females

When the Orange colour is inherited with the X chromosome it masks the base colour, which in Tonkinese may be Brown, Blue, Chocolate, Cinnamon, Lilac, Fawn or Caramel.

A Red, Cream or Apricot female is produced when the Orange gene is present on both pairs of the female sex chromosome ( X*X* ) - the Orange colour fully masks the base colour.
A Tortoiseshell female is produced when the Orange gene is present on just one of the pair of female sex chromosomes ( X*X ) - the Orange colour partly (or incompletely) masks the base colour in random patches (mottling).
An Orange male ( X*Y ) will only be produced if its dam is Orange - it must inherit the Y from its sire in order to be male, which means the X* has to be inherited from its dam. As it only has the one X chromosome the Orange colour fully masks the base colour.

In very rare circumstances, due to a genetic abnormality, a male cat may be X*XY, in which case it will be a Tortoiseshell male - and is usually sterile.

Brown Tortoiseshell Tonkinese in the three coat-patterns: