Cystic Fibrosis Punnett Square

Test yourself on Cystic Fibrosis Punnett Square

• In the Punnett square, both parents don't have cystic fibrosis but each carries the recessive allele. What is each parent's genotype?

• The Punnett square shows a 3:1 ratio of non-sufferers to sufferers among the children. What percentage of children are expected to not have cystic fibrosis?

• According to the Punnett square, what is the probability that a child of these two parents will have cystic fibrosis?

• Both parents carry one copy of the recessive cystic fibrosis allele, f. What must happen for their child to have cystic fibrosis?