Huntington's disease is caused by a single dominant allele. It is a lethal disease, yet it persists in the human population. Which of the following statements best describes why?
A. Huntington's disease is sex-linked and every human has at least one X chromosome; thus, the chances are extremely high for this allele to be maintained in the human population.
B. While lethal to a parent, Huntington's disease will not be lethal to the offspring since it can skip a generation.
C. Huntington's disease presents symptoms in mid-life, after most people have already had offspring.
D. Huntington's disease can present symptoms so mild that they appear to lack dominant expression of the allele in some individuals; in those cases, the allele is passed on to the offspring.
E. Even though Huntington's disease is lethal, it improves chances for reproduction before the person dies.
Answer: C
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