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Friedrich Miescher - 1896
In 1869, Friedrich Miescher discovered "nuclein" in the nuclei of human white blood cells, known as deoxyribonucleic acid (DNA).
His plan had been to isolate and characterize the protein components of white blood cells. He had arranged for a surgical clinic to send him pus-saturated bandages, he planned to wash out before filtering the white blood cells and their proteins.He came across a substance with chemical properties with very high phosphorous content and a resistance to protein digestion. -
Erwin Chargaff - 1950
In 1950,Chargaff discovered that DNA make up is species specific. He worked on the chemistry of nucleic acid with a method of analyzing the nitrogenous components and sugars of DNA from different species. His two major findings regarding the chemistry of nucleic acids were: that in any double-stranded DNA, the number of guanine equals to the number of cytosine and the number of adenine equals to the number of thymine, and the make up of DNA varies between species now known as 'Chargaff's Rules'. -
Alfred Hershey and Martha Chase - 1952
In 1952, Hershey and Chase experimented on what made up genetic material of bacteriophage.Bacteriophage is virus that infects bacterium.Performed with bacterium called Escherichia coli and virusT2 that infects E. coli.Radioactive chemicals decide protein capsid and DNA in T2virus.Two batches of T2 and E. coli and (radioactive S and P).Radioactive P found in bacterial pellet, DNA went bacteria. Discovered DNA is genetic material and not protein provided offspring of phosphorus bacteriophages. -
Rosalind Franklin - 1952
In 1952,Franklin conducted a large portion of the research which eventually led to the understanding of the structure of DNA. Her role was to set up and improve the X-ray crystallography. She was able to produce two sets of high-resolution photographs of DNA fibers.She calculated the strands and also deduced that the phosphates were on the outside of what was probably a helical structure. Her research came close to discovering the structure of DNA but she was beaten by Watson and Crick discovery -
James Watson and Francis Crick - 1953
In 1953, Watson and Crick discovered the double helix structure of DNA. Using X-ray data and model building, they were able to solve the puzzle that had baffled scientists such as Rosalind Franklin. Despite the fact that her photographs had been critical to Watson and Crick's solution, she was not honored. -
Matthew Meselson and Franklin Stahl - 1958
In 1958, Meselson and Stahl experiment proved that DNA copied itself through a semi-conservative process. They grew E. coli in a medium containing heavy nitrogen (N-15). They then added the E. coli to a medium containing regular nitrogen (N-14) and observed it over several generation. They contributed from Watson and Crick discovery of the double-helix structure of DNA in 1953. -
Works Cited Page
"The History of DNA Timeline." DNA Worldwide. N.p., 30 Sept. 2015. Web. 19 Jan. 2017.
"Friedrich Miescher." Biography of Friedrich Miescher | Simply Knowledge. N.p., n.d. Web. 19 Jan. 2017.
"Hershey and Chase." DNAbioC - Hershey and Chase. N.p., n.d. Web. 21 Jan. 2017.
