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1952: an X-ray diffraction image of DNA was taken by Raymond Gosling in May 1952, a student supervised by Rosalind Franklin. [30] 1953: DNA structure is resolved to be a double helix by James Watson, Francis Crick and Maurice Wilkins. [31] 1955: Alexander R. Todd determined the chemical makeup of nitrogenous bases.
In the 1940s and early 1950s, experiments pointed to DNA as the portion of chromosomes (and perhaps other nucleoproteins) that held genes. A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of molecular genetics.
The timeline begins at the Bronze Age, as it is difficult to give even estimates for the timing of events prior to this, such as of the discovery of counting, natural numbers and arithmetic. To avoid overlap with timeline of historic inventions , the timeline does not list examples of documentation for manufactured substances and devices unless ...
In May 1952, Raymond Gosling, a graduate student working under the supervision of Rosalind Franklin, took an X-ray diffraction image, labeled as "Photo 51", [206] at high hydration levels of DNA. This photo was given to Watson and Crick by Maurice Wilkins and was critical to their obtaining the correct structure of DNA. Franklin told Crick and ...
In the 1950s, three groups made it their goal to determine the structure of DNA. The first group to start was at King's College London and was led by Maurice Wilkins and was later joined by Rosalind Franklin. Another group consisting of Francis Crick and James Watson was at Cambridge. A third group was at Caltech and was led by Linus Pauling ...
Nucleic acid types differ in the structure of the sugar in their nucleotides–DNA contains 2'-deoxyribose while RNA contains ribose (where the only difference is the presence of a hydroxyl group). Also, the nucleobases found in the two nucleic acid types are different: adenine , cytosine , and guanine are found in both RNA and DNA, while ...
Photo 51 is an X-ray based fiber diffraction image of a paracrystalline gel composed of DNA fiber [1] taken by Raymond Gosling, [2] [3] a postgraduate student working under the supervision of Maurice Wilkins and Rosalind Franklin at King's College London, while working in Sir John Randall's group.
This discovery led to a more detailed investigation of DNA to determine its composition as well as its 3D structure. Using X-ray crystallography , the structure of DNA was discovered by James Watson and Francis Crick with the help of previously documented experimental evidence by Maurice Wilkins and Rosalind Franklin . [ 9 ]