Question

The allele for an attached earlobe is recessive. In the third generation, what are the odds that a carrier father and homozygous dominant mother will have a child with an attached earlobe?

A. 0 %
B. 25 %
C. 50 %
D. 100 %

Answer 1

The correct answer would be A. 0%

Let A and a be the dominant and recessive allele of the gene responsible for the attachment of earlobes respectively.

The father is a carrier of the trait. Thus, the genotype of the father would be Aa.

Similarly, the mother is homozygous dominant due to which her genotype would be AA.

The cross would produce the offspring with two types of genotypes which are Aa and AA.

Thus, none of the offspring would have attached earlobes as it is recessive trait.