History of molecular biology Crick and Watson built physical models using metal rods and balls, in which they incorporated the known chemical structures of the nucleotides, as well as the known position of the linkages joining one nucleotide to the next along the polymer. At King's College Maurice Wilkins and Rosalind Franklin examined X-ray diffraction patterns of DNA fibers. Of the three groups, only the London group was able to produce good quality diffraction patterns and thus produce sufficient quantitative data about the structure. In 1948 Pauling discovered that many proteins included helical (see alpha helix) shapes. Pauling had deduced this structure from X-ray
Timeline of United States discoveries chloride 1936 Elliptical galaxies 1936 Muons 1936 Vitamin E 1936 Sodium thiopental 1937 Niacin 1937 Electron capture 1938 Fluropolymers 1938 Animal echolocation 1938 Carme 1938 Lysithea 1940 Plutonium 1942 Cyanoacrylate 1943 Streptomycin 1944 Americium 1944 Curium 1946 Cloud seeding 1948 Warfarin 1948 Miranda 1948 Serotonin 1948 Tetracycline 1949 Nereid 1949 Berkelium 1950 Californium 1951 Barium stars 1951 Ananke 1952 Polio vaccine 1952 Einsteinium 1952 Rapid eye movement 1953 DNA structure In 1953, based on X-ray diffraction images and the information that the bases were paired, James D. Watson along with Francis Crick co-discovered what is now widely accepted as the