[Campbell Biology P.330] In Labrador retrievers, what is the specific genetic condition requ... | Practice Question

In Labrador retrievers, what is the specific genetic condition required for a 'chocolate Lab' phenotype?

  • A: Homozygous recessive for pigment deposition (ee).
  • B: At least one dominant allele for black pigment (B) and at least one dominant allele for deposition (E).
  • C: Homozygous recessive for pigment (bb) and at least one dominant allele for deposition (E).
  • D: Homozygous dominant for both genes (BBEE).

Explanation

The text states, 'For a Lab to have brown fur, its genotype must be bb; these dogs are called chocolate Labs.' It also clarifies that pigment must be deposited requiring at least one E allele . Therefore, the combination of bb with either EE or Ee represented as E results in the chocolate phenotype.