Coat colour red

LABOKLIN Service ID: 8947

The coat colour red is caused by a genetic variant of the Arhgap36 gene, which is located on the X chromosome and is therefore inherited in a sex-linked manner. The variant leads to a suppression of the production of the black-brown pigment eumelanin and promotion of the orange pigment pheomelanin.
As male cats only have one X chromosome, their coat colour is red if the red variant O is present (genotype X(O)/Y). If the variant is not present, they are not red (genotype X(o)/Y).
Female cats have two X chromosomes and need two copies of the red variant (genotype X(O)/X(O)) to show completely red fur. If the red variant is only present on one of the two X chromosomes (genotype X(O)/X(o)), red and non-red areas of the coat will be expressed due to random X inactivation, resulting in a tortoiseshell or calico pattern. With the X(o)/X(o) genotype, a cat does not show the coat colour red.

Method	FLP
Heredity	X-chromosomal
Duration	1-2 weeks after arrival of the sample in the lab