EXCLUSION OF TWO CANDIDATE GENES FOR BLACK HAIR FOLLICULAR DYSPLASIA IN DOGS

Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B5

A coat color abnormality in Large Munsterlander dogs was diagnosed as black hair follicular dysplasia using histology. In this disorder, the patches which are normally black, were a dull grey at birth, followed by subsequent hair loss in these areas beginning at about 4 weeks of age. A pedigree analysis of an affected inbred litter and literature review suggests that this disorder is inherited as an autosomal recessive trait. The eye color was an abnormal blue in all four affected pups and one was also deaf. Two candidate genes, chosen of the basis of the coat color affects, were explored in this family. A PCR-RFLP was found in the sire in the melanocyte stimulating hormone receptor gene and was ruled out by using linkage analysis. The tyrosinase related protein 2 causes "slaty" coat color in the mouse and an intronic microsatellite in dogs (An. Genet. 29:327, 1998) was used to also rule out this gene as the cause.