Question

Phenylketonuria (PKU) is an inherited disease caused by a recessive allele. If a woman and her husband, who are both carriers, have three children, what is the probability of each of the following

Answer 1

If they are both carriers , we can create a cross with Rr.

The probability of not even carrying PKU is 1/4 or 25%
The probability of carrying is 2/4 or 50%

And the probability of inheriting the disease PKU is 1/4 , 25%