For Labrador retrievers, black fur is dominant to yellow. a) Explain how two black dogs can have different genotypes. b) Could a black dog have the same genotype as a yellow dog

Please find the answers explained below

Explanation:

A) This question involves a Gene coding for fur color in Labrador retrievers (a dog). The allele for black fur (B) is dominant over the alllele for yellow fur (b). Based on the law of dominance by Gregor Mendel, the dominant allele will always mask the phenotypic expression of the recessive allele in a heterozygous state. The two fur colors have different alleles, however, when they come together to form a heterozygote, the black fur is still expressed. Naturally, a black furred Labrador retriever should have the genotype; BB but since the black fur is a dominant trait, another heterozygous genotype will arise as Bb.

B) No, the black dog cannot have the same genotype as yellow dog. This is because the black dog must always have at least one dominant allele (B) in order to be black while the yellow dog, due to the recessiveness of the yellow allele can only have the genotype; bb. Hence, a black dog can either be Bb or BB but a yellow dog can only be bb.