Hemophilia, color blindness, and Duchenne muscular dystrophy occur more often in males than females. Why? A) These traits are carried only on the X chromosome. B) Since there is no matching gene on the Y chromosome to compensate, the traits are expressed

The answer is E) These traits are carried only on the X chromosome and since there is no matching gene on the Y chromosome to compensate, the traits are expressed more readily in males. Hemophilia, color blindness, and Duchenne muscular dystrophy are caused by mutations on the X chromosome. Females have two X chromosomes while males have one X and one Y chromosome. Since females have two copies of the X chromosome, if one X chromosome has the mutation, the other X chromosome may carry a healthy version of the same gene. In males, however, there is no second X chromosome to compensate for the mutated one, so the mutation is expressed more readily. Therefore, males are more likely to have these diseases than females.