(bb) have amber eyes. Amber eyes vary from light brown to yellow, chartreuse, or gray. Dogs with melanin can occasionally see amber eyes.[article refers to Dr Sheila M. Schmutz] Blue eyes Blue eyes in dogs are often related to pigment loss in coatings. The merle gene results in a bluish iris, and merle dogs often have blue, walled, or split eyes due to random pigment loss. Some genetic variants cause Heterochromia iridum. The second way blue eyes can appear is when a dog has a lot of white fur on the face. Since the white areas cannot produce any pigment, pigment from the eyes and nose may be lost as well. The third way is when dogs are affected by albinism. A different gene, unaffected by coat color, can make the eyes blue. However, this gene is rare. It occurs occasionally in Border Collies and similar breeds, but is mostly seen in Siberian Huskies, which may have one or both eyes blue, regardless of their predominant coat color. Genetic testing and phenotype prediction In recent years genetic testing for the alleles of some genes has become available. Software is also available to assist breeders in determining the likely outcome of matings. Characteristics linked to coat colour The genes responsible for the determination of coat colour also affect other melanin-dependent development, including skin colour, eye colour, eyesight, eye formation and hearing. In most cases, eye colour is directly related to coat colour, but blue eyes in the Siberian Husky and related breeds, and copper eyes in some herding dogs are not known to be related to coat colour. The development of coat colour, skin colour, iris colour, pigmentation in back of eye and melanin-containing cellular elements of the auditory system occur independently, as does development of each element on the left vs right side of the animal. This means that in semi-random genes (M merle, s spotting and T ticking), the expression of each element is independent. For example, skin spots on a piebald-spotted dog will not match up with the spots in the dog's coat; and a merle dog with one blue eye can just as likely have better eyesight in its blue eye than in its brown eye. Loci for coat colour, type and length All known genes are on separate chromosomes, and therefore no gene linkage has yet been described among coat genes. However, they do share chromosomes