Cystic fibrosis is caused by a recessive mutant allele (cf). Two normal parents produce a child
with cystic fibrosis. What are the genotypes of the parents? a. CF/cf and CFICF b. CF/cf and
cf/cf c. Both are CF/cf d. CF/CF and cf/cf What is the probability of this family having four
children, 1 with cystic fibrosis, and 3 without cystic fibrosis? a. 0.14 b. 0.25 c. 0.047 d. 0.42
Solution
19. Answer is option C. Both are CF/cf
It is caused by the presence of mutations in both copies of the gene for the cystic fibrosis
transmembrane conductance regulator (CFTR) protein. Those with a single working copy are
carriers and otherwise mostly normal.
20.answer is option B. 0.25
Out of the 4 children, 0.25 will be healthy, 0.50 will be carriers and 0.25 will have disease..
Cystic fibrosis is caused by a recessive mutant allele (cf). Two norm.pdf
1. Cystic fibrosis is caused by a recessive mutant allele (cf). Two normal parents produce a child
with cystic fibrosis. What are the genotypes of the parents? a. CF/cf and CFICF b. CF/cf and
cf/cf c. Both are CF/cf d. CF/CF and cf/cf What is the probability of this family having four
children, 1 with cystic fibrosis, and 3 without cystic fibrosis? a. 0.14 b. 0.25 c. 0.047 d. 0.42
Solution
19. Answer is option C. Both are CF/cf
It is caused by the presence of mutations in both copies of the gene for the cystic fibrosis
transmembrane conductance regulator (CFTR) protein. Those with a single working copy are
carriers and otherwise mostly normal.
20.answer is option B. 0.25
Out of the 4 children, 0.25 will be healthy, 0.50 will be carriers and 0.25 will have disease.
