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Phoebus Levene
Levene deconstructed DNA and all of its components and found that it was a long-chain molecule and made up of four different nucleotides, sugar, ribose and phosphate. He also suggested that the nuclein kept a long string of nucleotides that are linked by phosphate connections however, he thought that the chain itself was short and the bases "continued in short patterns". -
Frederick Griffith
Frederick Griffith aided in the discovery that DNA was the molecule of inheritance. He experimented on mice with virulent and non-virulent pneumonia. He injected some mice with the virulent pneumonia (died) and others with the non-virulent pneumonia (lived). He then killed the virulent pneumonia and gave it to a mouse, it lived. Last he injected a mouse with non-virulent and virulent thats been heated, the mouse died. The virulent pneumonia died and passed on its traits to the non-virulent. -
Oswald Avery
By using Frederick Griffith's experimental results Avery showed that polysaccharides could stimulate the production of antibodies as an immune response and alterations caused in bacterium are passed into the next. He colaborated with Maclyn McCarty and Colin MacLeod to try to find out what this substance was that allowed the transference Griffith discovered. They found deoxyribonucleic acid (DNA) and found that genes are made of DNA and not proteins. -
Linus Pauling
Linus Pauling used x-ray diffraction and electron diffraction to explain the chemical bonds which allow atoms to be formed inside of molecules. He also wrote a paper in 1928 on the principles of determining the structure of complicated crystals (including ones existing in DNA) In 1946 he thought that genes contain two mutual complementary strands and two years later stated that polypeptide chains could be "coiled in a helical structure formed from amino acids" thus creating the "alpha helix." -
Erwin Chargaff
Erwin Chargaff helped in the discovery of the double-helix formation of DNA with his two rules. He looked at the base composition of DNA composition in numerous organisms and reported that they vary from one species to another. The two rules that he associated with this discovery were: in any double-stranded DNA the number of guanine equals the number of cytosine and the number of adenine units equals the number of thymine units and the composition of DNA varies from organism to another. -
Maurice Wilkins
As a colleague of Franklin, Crick, and Watson, Wilkins contributed into the discovery of a strand of DNA being in the shape of a double-helix. Before that however he used spectroscopy to learn as much as he could about DNA and its structure and parts. He and his partner Gosling also obtained the first clearly crystalline X-ray diffraction patterns from DNA fibers. -
Rosalind Franklin
A colleague of Francis Crick and James Watson, Rosalind Franklin took improved photographs of DNA found inside of the nucleus. She aided in the discovery of DNA being in a double-helix shape very much. From her crystallographic photos of hydrated DNA, Crick and Watson were able to figure out the double-helix shape of DNA and its components earning them noble prizes (along with Maurice Wilkins) but only after she had died from cancer. -
Hershey and Chase
Martha Chase and Alfred Hershey both worked together to figure out that DNA, not protein, carried information regarding a beings inheritance, even viruses. They find this by doing an experiment. Using virus cultures labeled with radioactive sulfur and DNA labeled with radioactive phosphorus, they allow them to infect bacteria. They then put it into a blender which separates phage particles from bacteria cells. Phage particles and sulfur are left in supernatant and phosphorus in the cell part -
Francis Crick
Francis Crick working along-side with James Watson came up with the double-helix structure of Deoxyribonucleic Acid (DNA). Using what they knew and what others had discovered about the contents of DNA they were able to map out how the strand of DNA would look with all of the proteins and sugars coexisting with each other. -
James Watson
James Watson and Francis Crick worked together to figure out the structure of a strand of DNA (the double-helix) using what they already knew about proteins and sugars (phosphate, cytosine, adenine, guanine, and thymine) and what previous biologists discovered -
Sources Cited
http://www.bookrags.com/biography
http://www.dnai.org/timeline/index.html
http://www.nndb.com/people/
http://www.accessexcellence.org/RC/VL/GG/hershey.php
http://library.thinkquest.org/
http://www.dnaftb.org/
http://dna.microbiologyguide.com/537-research-history-of-dna-Friedrich-Miescher-Phoebus-Levene/
