 What makes identical twins identical? Why does red hair run in families? Why are some traits passed down from generation to generation? For nearly 100 years, scientists had suspected the key could be a single molecule found in every living cell. That molecule is deoxyribonucleic acid, or DNA. By the 1940s, researchers determined that DNA carried the genetic information for each and every species. But they still had no clue as to what it looked like or how it functioned. That all changed in 1952 when this fuzzy picture gave us the first glimpse of the brave new world of the human genome. Taken by British scientist Rosalind Franklin, it marked a turning point in the quest to unlock life's code. Many scientists were competing to be the first to decipher DNA's structure, including James Watson and Francis Crick. The X-rays confirmed Watson and Crick's insight that DNA had to have a regular, repeating, twisting structure, a helix. It was thought lightly it would fold up as a helix. The opportunity was to just be a tangled mess. Far from a tangled mess, DNA's structure was elegant and simple, a double helix that captivated the imagination of scientists and the public alike. DNA is made up of only four chemicals called nucleotides, and known by the chemical letters A, C, G, and T. The real message of the double helix is not just this beautiful shape, not even the mechanism of replication, which is the first thing that drew Watson and Crick's attention. It's that the biological information, genetic information is digital. DNA is digital. Similar to how a computer uses only zeros and ones to create an infinite number of programs, DNA uses only four chemicals to create the astonishing variety of life we see around us. By the 1980s, the laborious task of ordering the roughly three billion nucleotides in the human genome, a process known as genome sequencing, was proceeding slowly in scattered laboratories across the world. That effort received an enormous boost from an unlikely place, the United States Department of Energy, or DOE. At the time, nuclear power was being hotly debated, in part because of concerns about the impacts of radiation on human health. The only way they could get at the heart of the problem, understand those impacts, we needed to sequence the human genome. The goal was clear. The challenge would be how to get there and who should lead the way.