Chapter 13.1, Problem 40E

Cystic fibrosis. From the Punnett square in Exercise 39, what is the probability that a child of two carriers will

a. be normal?

b. be a carrier?

Cystic fibrosis. Cystic fibrosis is a serious inherited lung disorder that often causes death in victims during early childhood. Because the gene for this disease is recessive, two apparently healthy adults, called carriers, can have a child with the disease. We will denote the normal gene by N and the cystic fibrosis gene by c to indicate its recessive nature.

a. Construct a Punnett square as we did in Example 9 to describe the genetic possibilities for a child whose two parents are carriers of cystic fibrosis.

b. What is the probability that this child will have the disease?