If your mother and father both are healthy but carry the allele for cystic fibrosis, which is caused by a recessive allele, the odds of you inheriting at least one allele for the disorder are ____.
A) 1/4
B) 1/2
C) 3/4
D) 1
E) 0

Question

Quizplus · Accepted Answer

Cystic fibrosis is inherited in an autosomal recessive manner. If both parents are carriers (heterozygous for the trait), each child has a 50% chance of inheriting one allele for the disorder (being a carrier) and a 25% chance of inheriting two alleles for the disorder (being affected). Therefore, the odds of inheriting at least one allele for the disorder are 75% or 3/4, combining the probabilities of being a carrier or being affected.

If Your Mother and Father Both Are Healthy but Carry