 A number of geneticists, structural chemists, and physicists descended on the structure of DNA in the 1950s (Olby 1994). It was James Watson and Francis Crick at the University of Cambridge who first determined that DNA was a double-helix (Watson and Crick 1953). Utilizing Watson’s genetic expertise, Crick’s work in theoretical physics, and Rosalind Franklin’s x-ray crystallographic images of DNA (appallingly, without her consent or even knowledge), Watson and Crick built a model of DNA showing two polynucleotide strands spiraling around one another (de Chadarevian 2002; Maddox 2002). The strands were made up of a sequence of nucleic acids—combinations of adenine (A), thymine (T), cytosine (C), and guanine (G), such that an adenine on one strand hydrogen-bonded with a thymine on the other and a cytosine on one strand hydrogen-bonded with a guanine on the other (entry:  models in science).