Question

one parent is a carrier of the cystic fibrosis gene, while the other parent does not carry the allele. can their child have cystic fibrosis? yes no

Explanation:

Cystic fibrosis is an autosomal recessive disorder. Let's assume the normal allele is \(A\) and the mutant allele is \(a\). The carrier parent has the genotype \(Aa\) (has one normal and one mutant allele), and the non - carrier parent has the genotype \(AA\) (has two normal alleles). When they have children, the possible genotypes of their children are obtained from the following cross:

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The possible genotypes of their offspring are \(AA\) and \(Aa\). For a child to have cystic fibrosis, the child needs to have the genotype \(aa\) (homozygous recessive). Since neither parent can contribute two mutant alleles (\(a\)), a child with genotype \(aa\) is not possible.

Answer:

B. No