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Miescher
Miescher was given the task of researching the composition of lymphoid cells white blood cells though Miescher did most of his work in 1869, his paper on nuclein wasn't published until 1871. Although Miescher did most of his work in 1869, his paper on nuclein wasn't published until 1871. He also examined the metabolic changes that occur in salmon when they spawn would be years before the role of nucleic acids were recognized. Miescher, himself, believed that proteins were molecules of heredity. -
Griffith
In 1928, Griffith performed a series of experiments using two live strains of pneumonia bacteria: one pathogenic and the other, non-pathogenic. The smooth coat strain was lethal, while the rough coat strain was non-lethal to mice. Griffith killed the pathogenic strain by applying heat. The mice contracted pneumonia and died.In 1944, a group of scientists identified the transforming factor as deoxyribonucleic acid or DNA. -
Avery
Avery worked on many strains of bacteria, applying different immunological and chemical methods. In 1913, Avery published a clinical study of the tuberculosis bacterium. This work attracted the attention of Dr. Rufus Cole, the director of the Rockefeller Institute Hospital, who offered Avery a job at the Rockefeller. Avery did his Pneumococcus work at the Rockefeller and stayed there until his retirement in 1948. -
Chargaff
In 1944 Chargaff began his investigations into the composition of DNA. By 1950 he had experimentally determined and published certain crucial facts that led directly to the correct elucidation of its molecular structure.He demonstrated 3 rules, known as Chargaff's rules, which state that in DNA:
1: The number of Adenine always equals the number of Thymine
2: The number of Cytosine always equals the number of Guanine
3: The number of purines always equals the number of pyramidines -
Franklin and Wilkins
Wilkins began using optical spectroscopy to study DNA in the late 1940s. In 1950 he and Gosling obtained the first clearly crystalline X-ray diffraction patterns from DNA fibers.The discovery of the structure of DNA in 1953 revealed the physical and chemical basis of how characteristics are passed down through the generations and how they are expressed in individual organisms. -
Hershey and Chase
Hershey and Chase found that
When bacteriophages containing radioactive, were allowed to infect nonradioactive bacteria, all the infected cells became radioactive and, much of the radioactivity was passed on to the next generation of bacteriophages.
From these experiments, it was clear that the DNA component of the bacteriophages is injected into the bacterial cell while the protein component remains outside. However, it is the injected component -
Watson and Crick
Watson and Crick's discovery was made possible by recent advances in model building, or the assembly of possible three-dimensional structures based upon known molecular distances and bond angles, a technique advanced by American biochemist Linus Pauling. Watson and Crick were not the discoverers of DNA, but rather the first scientists to formulate an accurate description of this molecule's complex, double-helical structure. -
Linus Pauling
Linus Pauling's contribution to DNA research was the triple-helix DNA model. This model, which was published in 1953, was incorrect, but it did lay the foundation for James Watson and Francis Crick's correct model of DNA as a double helix.Pauling's model is incorrect because it shows the helical core being formed by phosphates. This is impossible under normal cellular conditions since phosphates, which are negatively charged, would repel each other when forced together. -
Frederick Sanger
Sanger was a conscientious objector during the war. He stayed at Cambridge to do a Ph.D. with Albert Neuberger, on amino acid metabolism. After his Ph.D. in 1943, Sanger started working for A.C. Chibnall, on identifying the free amino groups in insulin. In the course of identifying the amino groups, Sanger figured out ways to order the amino acids. He was the first person to obtain a protein sequence.He won his first Nobel Prize for Chemistry in 1958 for his work on the structure of protein.
