In a certain dog breed, the allele B for a black coat is dominant, and the allele b for a spotted coat is recessive. What genotypes for this dog breed would lead to a spotted phenotype?
OBB
O Bb
BB and bb
O bb
The correct genotypes that would lead to a spotted phenotype in this dog breed are:
O Bb: In this genotype, the dog has one dominant allele (B) for a black coat and one recessive allele (b) for a spotted coat. The dominant allele determines the coat color to be black, but because there is a recessive allele present, the coat will still show spots.
O bb: In this genotype, the dog has two recessive alleles (bb) for a spotted coat. Both alleles being recessive means that the coat color will be spotted.
The other genotypes mentioned (OBB and BB) both have at least one dominant allele for a black coat, so they would lead to a black coat phenotype.