The grizzle coat color pattern in some breeds of dog is inherited in an Autosomal Dominant manner meaning that dogs only need to inherit one copy of Eg to have the characteristic grizzle patterning. (pawprintgenetics.com)
The Eg variant of the MC1R gene produces a characteristic coat color pattern consisting of a black pigmented widow's peak on the head of the dog with other black tipped hairs on the back of the dog similar to some sable or saddle tan colorations. (pawprintgenetics.com)
Dogs with only one copy of Eg will pass on Eg to 50 % of their offspring and will produce puppies with grizzle coat color patterns approximately 50 % of the time depending on the genotypes at the Em, K, and A loci of both partner dogs. (pawprintgenetics.com)