If the parent genotypes are Aa and Aa, what is the expected genotype frequency of their offspring?

To determine the expected genotype frequency of the offspring from the parent genotypes Aa and Aa, we can utilize a Punnett square, which helps visualize the combinations of alleles passed from the parents to the offspring.

The parent genotypes are both heterozygous (Aa). When we set up the Punnett square, we place the alleles of one parent along the top and those of the other parent along the side. This yields:

• From the first parent (top): A and a

• From the second parent (side): A and a

Filling out the Punnett square gives us:

• AA (from A and A)

• Aa (from A and a)

• Aa (from a and A)

• aa (from a and a)

When we tally up the combinations:

• There is 1 occurrence of AA,

• 2 occurrences of Aa,

• 1 occurrence of aa.

This results mathematically in the following ratios:

• 1/4 of the offspring are AA,

• 1/2 of the offspring are Aa,

• 1/4 of the offspring are aa.

Thus, the expected genotype frequency for the offspring is correctly characterized by the ratio of 1/4 AA, 1