History of genetics code for specific proteins, leading to the "one gene, one enzyme" hypothesis. Oswald Avery, Colin Munro MacLeod, and Maclyn McCarty showed in 1944 that DNA holds the gene's information. In 1952, Rosalind Franklin and Raymond Gosling produced a strikingly clear x-ray diffraction pattern indicating a helical form, and in 1953, James D. Watson and Francis Crick demonstrated the molecular structure of DNA. Together, these discoveries established the central dogma of molecular biology, which states that proteins are translated from RNA which is transcribed by DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses.
Molecular models of DNA 1953. That same year, Maurice F. Wilkins, A. Stokes and H.R. Wilson, reported the first X-ray patterns of "in vivo" B-DNA in partially oriented salmon sperm heads. The development of the first correct double helix molecular model of DNA by Crick and Watson may not have been possible without the biochemical evidence for the nucleotide base-pairing ([A---T]; [C---G]), or Chargaff's rules. Although such initial studies of DNA structures with the help of molecular models were essentially static, their consequences for explaining the "in vivo" functions of DNA were significant in the areas of protein biosynthesis and the quasi-universality of the