 Several researchers turned their efforts to elucidating the structure of DNA (Judson 1979: Ch. 2; Morange 2020: Ch.11; Olby 1974: Section V). Among them were James Watson (born 1928) and Francis Crick (1916–2004). They used data from DNA X-ray crystallography produced by Maurice Wilkins (1916–2004), Rosalind Franklin (1920–1958), and co-workers, and adopted the style of reasoning and use of ball-and-stick models of molecules pioneered by Linus Pauling (1901–1994). DNA was already known to consist of a sugar-phosphate structure and the four bases cytosine (C), guanine (G), adenine (A) or thymine (T). Based on additional evidence, Watson and Crick eventually came to consider a double helix model with the bases on the inside and a pairing of A with T and G with C, which was published in April 1953. Shortly thereafter they published another paper which spelled out the consequences for genetics (Watson &amp; Crick 1953a,b). The model suggested a mechanism of DNA replication according to which the two chains of the DNA separate and each acquires a novel complementary strand on the basis of base pair complementarity. Hence it explained the previously postulated autocatalytic properties of genes. Seymour Benzer (1921–2007), working with phage was able to push the resolution of genetic analysis to a level below the gene, by mapping mutation loci within genes (Holmes 2006). His work supported the DNA model as it showed that not only genes, but also their components were arranged in a linear sequence and suggested that single bases could be the locus of mutation. Benzer concluded that the understanding of the classical gene as unit of mutation, recombination and function needed to be revised (Benzer 1957). He suggested the novel terms “muton”, “recon” and “cistron,” where only the latter gained some currency to refer to genes as units of function.