In Labrador retrievers, black coat color is dominant to brown.Suppose that a black Lab is mated with a brown one, and the offspring are 4 black puppies and 1 brown.What can you conclude about the genotype of the black parent? (Assume that B is the allele for black and b is the allele for brown.)
A)The genotype must be BB.
B)The genotype must be bb.
C)The genotype must be Bb.
D)The genotype could be either BB or Bb.
E)The genotype cannot be determined from these data.

Question

Quizplus · Accepted Answer

Since the mating produced a brown puppy, the black parent must have contributed a recessive b allele, indicating its genotype is Bb. Black is dominant (B), and brown is recessive (b). For a brown puppy to occur, it must inherit a b allele from both parents.

In Labrador Retrievers, Black Coat Color Is Dominant to Brown