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)

Question

Responses

Both parents are homozygous for the trait.
Both parents are homozygous for the trait.

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

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

Only one parent is homozygous.

Answer 1

If two parents with black hair (the dominant phenotype) have an offspring with blond hair (the recessive phenotype), it indicates that both parents must carry the allele for blond hair (the recessive trait).

The possible genotypes for parents with black hair are:

• Homozygous dominant (BB)
• Heterozygous (Bb)

For a child to express the recessive trait (blond hair), it must inherit two recessive alleles (bb), one from each parent. This is only possible if both parents are at least heterozygous (Bb), meaning they carry one dominant allele and one recessive allele.

Thus, the true statement about the parents’ genotypes is:

Both parents are heterozygous for the trait.