• Describes the chemical and structural bases of heredity and genome organization as the core of gene expression, integrating DNA structure, chromatin context, and nuclear architecture across early work. Examples include DNA structure [5], nucleic acid constituents [11], chromosomal proteins [6], chromonemata in mitosis [13], and nucleic acids in plant nuclei [20].

• Nucleic acid metabolism and turnover as probes of gene expression, using in vivo/in vitro labeling to trace synthesis, decay, and incorporation into nucleic acids. Represented by 14C-formate/glycine/adenine/phosphate incorporation [3], turnover studies [9], 14C-formate into bases [14], adenine incorporation in mice [15], and rat liver/hepatoma turnover [18].

• Analytical and chemical methodologies for nucleic acids—chromatography, base/nucleoside quantification, and molecular biology assays—that established practical routes to studying nucleic acids and gene expression. Chromatographic identification of bases and nucleosides [1] complements structural/nucleic acid analyses [11].

• Enzymology and protein–nucleic acid interfaces as determinants of gene expression; early framing of enzymes as structural/functional units, with work on enzymes in biology and plant amylolysis illustrating enzyme-catalysis roles [2], [12].

• Mammalian genetics and tissue-context nucleic acid dynamics, linking molecular biology to growth, liver/hepatoma metabolism, and skeletal genetics; studies include rat liver/hepatoma nucleic acids [18], adenine incorporation in mice [15], mouse skeletal genetics [7], and pigment-related histology [16].