Question

If two parents have the genotypes AA x aa, the probability of having an aa genotype in the F${}_1$ generation is

• A. 25 percent
• B. 50 percent
• C. 75 percent
• D. None of the above

Answer 1

The correct option is D None of the above

If one of the parents is homozygous AA, then it can form only one type of gamete, having a dominant allele A and other parent is also homozygous aa, so it can also form only one type of gamete a. Fusion of these gametes will form only one type of individual Aa. Hence, probability of having aa genotype is 0.

Thus, the correct answer is option D.