Coat Colour E-Locus (Amber)

Amber (previously called X-Colour) is a yellow recessive coat colour observed in the Norwegian Forest Cat (NFC) population and apparently absent in other cat breeds. The colour is caused by a single MC1R allele on a locus called e. In general, the extension (E) locus MC1R interacts with the agouti locus to produce black and reddish pigments. The E-locus has two variants (alleles). It is presumed that (almost) all cats have two copies of the dominant allele E, meaning they can produce both red and and black pigment. If this is not the case, Amber coat colour can arise.