The possible genotypes for dogs with pink gums would be BB and Bb. The possible genotypes for dogs with black gums would be BB and Bb. The possible genotypes for dogs with pink gums with black spots would be Bb.
In genetics, capital letters are used to represent dominant traits and lowercase letters are used to represent recessive traits. Therefore, in this case, the genotypes for dogs with pink gums would be BB and Bb, the genotypes for dogs with black gums would be BB and Bb, and the genotypes for dogs with pink gums with black spots would be Bb.
For example, a dog with pink gums and black spots could have the genotype Bb, indicating that it has inherited the dominant B allele (black gums) from one parent and the recessive b allele (pink gums) from the other parent. The presence of the pink gums with black spots phenotype indicates that the dog has inherited the b allele from one parent, which causes the pink gums with black spots phenotype to be expressed.