• Quantitative mapping of DNA chemical composition across tissues and organisms established DNA's nucleotide makeup as a stable chemical foundation, leveraging electrometric titration, Feulgen cytochemistry, and direct nucleotide analyses [16], [5], [13], [2], [17].

• Analytical chemistry and chromatographic/separation technologies enabled systematic nucleic acid analysis, decomposing nucleic acids into purines, pyrimidines, and ribonucleotides via paper chromatography, anion-exchange methods, and quantitative ribonucleotide separations [3], [9], [7], [8].

• Emergence of structural and chemical theory around nucleic acids, treating DNA as a polymer of discrete units with specific base composition, laying groundwork for later replication models [4], [2], [6].

• DNA replication and phage biology as a testbed for the roles of nucleic acids vs proteins, including separate functions in growth and DNA composition in phage, advancing the view of DNA as genetic material [20], [19].