Duchenne Muscular Dystrophy Is a Serious Condition Caused by a Recessive

Multiple Choice

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition?

A) Women can never have this condition.
B) One-half of the daughters of an affected man would have this condition.
C) One-fourth of the daughters of an affected father and a carrier mother could have this condition.
D) Very rarely: it is rare that an affected male would mate with a carrier female.
E) Only if a woman is XXX could she have this condition.