Genetics: How Nature Reads the Code

Although geneticists agree that the giant molecules of DNA (deoxyribonucleic acid) contain the coded information that controls the development of living organisms, they have yet to decipher the message. But the varieties of experimental attack seem almost unlimited as stubborn scientific cryptologists continue to study one of nature's most intractable secrets.

German Chemists Peter Karlson and Adolf Butenandt of the University of Munich collected three tons of silkworm pupae, ground up the little animals, then carefully processed the mess to extract 100 milligrams (one three-hundredth of an ounce) of a hormone called...