Question

If two parents have black hair, a dominant phenotype, and one of their offspring has blond hair, a recessive phenotype, which would be a true statement about the parents’ genotypes?(1 point)
Responses

Only one parent is heterozygous.
Only one parent is heterozygous.

Only one parent is homozygous.
Only one parent is homozygous.

Both parents are heterozygous for the trait.
Both parents are heterozygous for the trait.

Both parents are homozygous for the trait.

Answer 1

In this scenario, black hair is a dominant phenotype (let's represent it with the allele "B") and blond hair is a recessive phenotype (let's represent it with the allele "b"). Since the offspring has blond hair (bb), it must have received one recessive allele (b) from each parent.

For the offspring to have a recessive phenotype (bb), both parents must have at least one recessive allele (b) to pass on. This means that both parents must be at least heterozygous (Bb), as a homozygous dominant (BB) parent could not provide a recessive allele.

Therefore, the correct answer is:

**Both parents are heterozygous for the trait.**