If your mother and father are both heterozygous for Huntington's disease, which is caused by a dominant allele, the odds of you having the disorder are ____.
A) 1/4
B) 1/2
C) 3/4
D) 1
E) 0

Question

Quizplus · Accepted Answer

Since Huntington's disease is caused by a dominant allele, and both parents are heterozygous (Hh), the possible genetic combinations for their child are HH (homozygous dominant), Hh (heterozygous), and hh (homozygous recessive). Only the hh combination would not result in the disease. The odds of hh (not having the disease) are 1/4, thus the odds of having the disease (HH or Hh) are 3/4.

If Your Mother and Father Are Both Heterozygous for Huntington's