by Jette Eva Madsen.

What is the genetic basic for chocolate and lilac? Where does the color come from?

Throughout the last year there has been a lot of discussion going on concerning the new variants of Norwegian Forest Cat. The variants are the chocolate and lilac colors.

The chocolate variant is a diluted variant of the black cat. The blue cat is also a diluted kind of a black cat, but the blue is a different kind of dilution concerning a different gene.

The gene that causes the usual blue dilution known amongst NFC's from the early days of the breed is the 'D' gene. The blue cat is the double recessive for the 'd' mutation and the genotype is written 'dd'.

The chocolate color is the double recessive for the gene called 'B'. Therefore the genotype of the chocolate cat is written 'bb'.

The lilac cat is not a mutation in itself. The lilac color is brought about as a result of the two other diluting genes. This means that the lilac is a mixture of a cat carrying the double recessive for both the blue dilution and the chocolate dilution. The genotype is written 'ddbb'.

The chocolate gene was first brought into cat breeding with the introduction of the cats of foreign type. It has always been closely linked to the Siamese and Burmese cats and it is therefore expected that the risk of getting the gene for Siamese or Burmese points into the breed at the same time is very high.

Furthermore there are two mutations of the 'B' gene. One is the traditional bb, chocolate. The other is a lighter color 'b'. The cat homozygotic, b'b' is called sephia. In a breed like ours it is very difficult to distinguish between the two variants. Alone since most of our cats are also agouti and the fact that most breeders till this day has not breed for clear colors makes it nearly impossible to distinguish which variants of the 'B' gene we have in our cats.

So the issue if we want chocolate and lilac is more complicated than it seems at first. What kind of chocolate are we talking about, bb or b'b'? It is at all possible to distinguish between the two lilac variants ddbb and ddb'b'? What will happen if suddenly a pointed (Burmese or Siamese) kitten appears sometime in the future? How does the agouti gene influence the possibility of distinguishing between the two chocolate variants? How does the silver gene influence the chocolate genes?

Well the questions are numerous. Who can give the answers?

PS: Perhaps it seems strange to predict the birth of a pointed NFC but actually short time ago in one of our close lying breeds namely the Maine Coon a pointed kitten was suddenly born. Skilled breeders would probably have killed the kitten or better sold it as a pet without pedigree but this happened to a very inexperienced breeder who decided to take the cat to a show because it looked strange. This happened in Europe in well known lines. The cat was disqualified because in the present standard of FIFe points are not allowed for Maine Coons. What will happen if more kittens are born?