Holly Ahern | Apr 29, 1990 | 5 min read
For many years, geneticists determined the genetic makeup of organisms by examining the physical characteristics of their offspring. But with the discovery of the structure of the DNA double helix, first published by James D. Watson and Francis H.C. Crick in 1953 (Nature, 171:964-7), the science of genetics was forever changed. Scientists soon developed techniques to study the genetic message found in all living cells at the molecular level. One of most important of these methods was the use of