A cross is made between two parents, both with
genotype Aa. What is the probability that an
offspring will have the genotype aa?
Question 3 options:
1/8
1/4
1/2
3/4
The probability can be determined using a Punnett square to show the possible genotypes of the offspring.
Aa x Aa:
A a
------
A | AA | Aa
------
a | Aa | aa
From the Punnett square, we can see that there are 4 possible genotypes for the offspring: AA, Aa, Aa, and aa.
Since we are interested in the probability of the genotype aa, there is only 1 out of the 4 possible genotypes that satisfy this condition.
Therefore, the probability that an offspring will have the genotype aa is 1/4.
So, the correct answer is 1/4.