Assume that developing a sixth toe is a recessive trait that is controlled by a single pair of genes.If a child has six toes,but both the child's biological parents have normal feet,you can conclude that
A) one parent is heterozygous for the trait, and the other parent is homozygous.
B) both parents are heterozygous for the trait in question.
C) the child has been adopted.
D) both parents are homozygous for the trait in question.

Question

Quizplus · Accepted Answer

Since developing a sixth toe is a recessive trait, both parents must be carriers of the gene but not express it. This means that both parents must be heterozygous for the trait. When they have a child, there is a 25% chance that the child will inherit two recessive genes for the trait and express it, resulting in six toes. Therefore, the best choice is B, both parents are heterozygous for the trait.

Assume That Developing a Sixth Toe Is a Recessive Trait