Cystic fibrosis is caused by a recessive gene.If C = normal and c = cystic fibrosis,how can a child with cystic fibrosis have two parents who do not have cystic fibrosis?
A) The child has a genotype of CC.
B) The parents have genotypes of CC and Cc.
C) The parents have genotypes of Cc and Cc.
D) The child has a genotype of Cc.

Question

Quizplus · Accepted Answer

Both parents must be carriers of the cystic fibrosis gene (Cc) but do not express the disease themselves. They have a 25% chance of having a child with cystic fibrosis (cc) if both parents pass on the recessive gene.

Cystic Fibrosis Is Caused by a Recessive Gene