Coat Colour Testing
It is important to understand that there are many genes involved in canine coat colour. The formation of breeds and the introduction of breed standards have restricted the number of recognised coat colour variants in each breed. As a result, undesirable colours and variations have been eliminated from each breed through selective matings, over many generations.
Today, most breeds exhibit only a limited number of coat colour variations. One of the reasons for this is that many of the genes involved have become fixed and only a specific allele of the gene remains. Another reason is that many of the colour variations are recessive and require two copies of the allele in order to exhibit the colour.
Currently, genetic testing can interrogate 6 of the genes involved however, there are clearly many others.