Question

Cystic fibrosis is an autosomal recessive disease. If parents, both suffering from cystic fibrosis, have children, what is the probability that one of their children will have the disease?
A)25%B)50%C)75%D)100%

Answer 1

The answer should be D, 100% chance

Answer 2

Answer:

100%.

Explanation:

Cystic fibrosis may be defined as the hereditary disease that affects the digestive system and the lungs of an individual. Cystic fibrosis is an autosomal recessive disease.

The autosomal recessive disease can only be expressed in the homozygous recessive condition. Since, both the parents are affected this means they have the genotype aa. The cross between the parents (aa × aa), the progeny will be of aa. There is 100% chances that their first progeny will be diseased.

Thus, the correct answer is option (D).