Starting with the double-helical structure of DNA in 1953, the story of molecular biology has featured more characters than a Russian novel. Biologists have identified tens of thousands of molecules that direct and shape the organized chaos within the body's cells, and they have exploited those findings with thousands of drugs and treatments.
For decades the stars of the drama came from two camps: DNA, or deoxyribonucleic acid, which acts as a near permanent repository of genetic information, and proteins, which do the genes' handiwork. Protein discoveries have led to such medical advances as synthetic insulin, interferon and next-generation anticancer drugs. And gene therapy, using modified bits of DNA, has made headway against hemophilia, hereditary blindness and other previously intractable diseases.