Category:Extension gene (E) cat coats

Mutations in the MC1R (melanocortin 1 receptor) gene (E locus) cause extreme red-to-yellow hair or coat colours in various species. In cats, three alleles have been described at the E locus, including the e recessive amber allele in Norwegian Forest cats and the er recessive russet allele in Burmese cats. In Kurilian Bobtails, breeders described brown tabby cats born with a warm reddish tone and exhibiting a modification of their original colour during their first year of life. Kittens brighten and adults show an apricot-red colour. Eumelanin disappears from hairs and cats become very similar to sex-linked red cats. Pedigree data showed an autosomal recessive mode of inheritance. A comparison of the MC1R sequences from variant Kurilian cats, known carriers of the colour, non-carriers and an unrelated brown tabby domestic shorthair cat revealed a single homozygous difference. The mutation will be easily detectable with a genetic test and be named the ec (copal) allele in cats in common format with the amber and russet alleles.