Question

For this Punnett Square, "A" is defined as being the dominant normal allele and "a" is the recessive abnormal one that is responsible for an inherited disorder. If both the mother and father are healthy carriers (Aa), what are the chances that their offspring will have the recessive disorder (aa)? Punnett Square A a A AA Aa a Aa aa 2% 25% 50% 75%

Answer 1

25% since both have to be "a" for the recessive gene to actually appear in the offspring, I would say that there is a 25% chance.