Vitamin-D resistant rickets is a sex-linked dominant trait, which leads to softening of the bones, which can cause fractures and deformities. Rickets is often due to a deficiency of vitamin D; however, with vitamin- D resistant rickets, ingestion of vitamin D is ineffective. Maria's mother is normal and does not display any symptoms of this disease. Maria's father, however, has the disease. Maria marries a man that does not have the disease. What is the probability that they will have a son that has the disease?
A) 0%
B) 25%
C) 50%
D) 75%
E) 100%

Question

Quizplus · Accepted Answer

Maria must be heterozygous for the trait because her mother did not have the disease. Thus, there is a 50% chance that any of her sons will have the disease.

Vitamin-D Resistant Rickets Is a Sex-Linked Dominant Trait, Which Leads