The inheritance of the piebald spotting pattern and its variation in Holstein-Friesian cattle and in Landseer-Newfoundland dogs.

The black and white spotting patterns of Landseer dogs are divided into qualitatively recognizable phenotypic classes. Breeding data were obtained from the Swiss Dog Stud Book (SHSB) and from breeders' recent records. A plausible interpretation assumed qualitative inheritance of the generally accepted piebald spotting gene sp1 with at least two modifiers, s2 and s3. The modifier genes are regarded as minor spotting genes and may be responsible for white markings in the related Newfoundland breed which has been cross-bred with Landseers. The proposed scheme of polygenic inheritance can also be applied to the piebald spotting pattern of Holstein-Friesian cattle, using breeding data from literature.