In the 1980s and 1990s,positional cloning led to the discovery of genes that
A) encode all proteins in the human genome. B) cause hemophilia, fragile X syndrome, and colorblindness. C) cause several types of cancers. D) cause Duchene muscular dystrophy, cystic fibrosis, and Huntington disease. E) make a person susceptible to radiation-induced damage to DNA.