Huntington's disease is caused by the allele H, which is completely dominant to the normal recessive allele h. Consider a couple where the man has the genotype Hh, and the woman has the genotype hh. What is the chance that their first child will develop Huntington's disease?
A) 0%
B) 25%
C) 50%
D) 75%

Question

Quizplus · Accepted Answer

Each time the couple conceives a child, there is a 50% chance that the child will inherit the H allele from the father and a 50% chance that the child will inherit the h allele from the mother. If the child inherits the H allele, they will develop Huntington's disease because it is completely dominant. If the child inherits the h allele from both parents, they will not develop the disease because they do not have the H allele. Therefore, there is a 50% chance that their first child will develop Huntington's disease.

Huntington's Disease Is Caused by the Allele H, Which Is