Changes in melanin granules in the fox due to coat color mutations.

Hair samples from 11 different coat color phenotypes of the fox (Vulpes vulpes) were examined microscopically to determine the effects of several mutations on melanin granule color and distribution. Standard silver (b/b) causes the production of eumelanin rather than the phaeomelanin produced in wild-type red fox. Fromm brown (bf/bf) and Collicott brown (cb/cb) change the shape of the granules and convert eumelanin to brown and dark brown, respectively. The color dilution of Eastern Pearl (pe/pe) and Mansfield Pearl (pm/pm) is caused by clumping of granules in specific manners. Hairs from animals expressing more than one mutant gene, such as Amber (b/b pe/pe bf/bf), show the color and distribution of granules expected from interactions of independent loci.