Question

Cystic fibrosis is an inherited autosomal recessive disease. If a woman with cystic fibrosis has children with a man who does not have cystic fibrosis and is not a carrier, what percent of their children are expected to have cystic fibrosis?

Answer 1

None of the children of a woman with cystic fibrosis and a man with no defective alleles will have the disease, but all will be carriers.

Step-by-step explanation:

Cystic fibrosis is an autosomal recessive genetic disease, meaning that it requires two copies of the defective gene for the disease to manifest. If a woman with cystic fibrosis, who would have two copies of the recessive gene (ff), has children with a man who has two normal alleles (FF), all of their children will inherit one normal allele from the father and one defective allele from the mother, making them carriers of the disease.

Their children will not have cystic fibrosis because they have the genotype Ff (one normal and one defective allele), which only makes them carriers. Therefore, 0 percent of their children are expected to have cystic fibrosis, but they will have a 100% chance of being carriers.