Between 1944 and 1953, many scientists sought information that might answer the most significant and intriguing question in the history of biology: How does DNA serve as the genetic basis for the living process? Researchers believed the answer depended strongly on the chemical structure of the DNA molecule, given the complex but orderly functions ascribed to it.
These efforts were rewarded in 1953 when James Watson and Francis Crick set forth their hypothesis for the double-helical nature of DNA. The assumption that the molecule’s functions would be clarified more easily once its general structure was determined proved to be correct. In this chapter we initially review the evidence that DNA is the genetic material and then discuss the elucidation of its structure.
- 10.1 The Genetic Material Must Exhibit Four Characteristics
- 10.2 Until 1944, Observations Favored Protein as the Genetic Material
- 10.3 Evidence Favoring DNA as the Genetic Material Was First Obtained During the Study of Bacteria and Bacteriophages
- Transformation Studies
- The Hershey–Chase Experiment
- Transfection Experiments
- 10.4 Indirect and Direct Evidence Supports the Concept that DNA Is the Genetic Material in Eukaryotes
- Indirect Evidence: Distribution of DNA
- Indirect Evidence: Mutagenesis
- Direct Evidence: Recombinant DNA Studies
- 10.5 RNA Serves as the Genetic Material in Some Viruses
- 10.6 The Structure of DNA Holds the Key to Understanding Its Function
- Nucleic Acid Chemistry
- Base Composition Studies
- X-Ray Diffraction Analysis
- The Watson–Crick Model
- 10.7 Alternative Forms of DNA Exist
- 10.8 The Structure of RNA Is Chemically Similar to DNA, but Single Stranded
- 10.9 Many Analytical Techniques Have Been Useful During the Investigation of DNA and RNA
- Molecular Hybridization Techniques
- Reassociation Kinetics and Repetitive DNA
- 10.10 Nucleic Acids Can Be Separated Using Electrophoresis
