DNA Discovery

P.A. Levene

Dec 13, 1920

Determined the basic structure of nucleotides that make up DNA. Nucleotides are subunits of nucleic acids. The two nucleic acids found in living cells are DNA and RNA.

Fredrick Griffith

Dec 12, 1928

Griffith did the first major experiment that led to the discovery of DNA as the genetic material. He studied two strains of bacteria. He found one strain could be transformed into the other form.

Oswald Avery

Dec 12, 1944

Identified the molecule that transformed the R strain of Bacteria into the S strain. He isolated different macromolecules like lipids, DNA and proteins from killed S cells then exposed live R cells to the S strain DNA. This transformed the bacteria into S cells.

Maurice Wilkins

Dec 13, 1947

Worked with a technique called x-ray diffraction, which was aiming x-rays at the DNA molecule. He did his work at King's college located in London.

Erwin Chargaff

Dec 13, 1948

Ananlyzed the amount of adenine, gaunine, thymine, and cytosine in the DNA of various species. He found that the amount of gaunine equates to the amount of cytosine, while the amount of adenine equates to the amount of thymine within a species. Chargaff's rule: C = G T = A

James Watson

Dec 13, 1950

Worked at the Cambridge University in England. He worked along side of Francis Crick. Using both Chargaff and Franklin's data, together they built a model of the double helix that was based off of the others research. Figured that it is the characteristic of DNA replecation through which the parent strand can determine the sequence of a new strand.

Francis Crick

Dec 13, 1950

Worked at the Cambridge University in England. He worked along side of James Watson. Using both Chargaff and Franklin's data, together they built a model of the double helix that was based off of the others research. Figured that it is the characteristic of DNA replecation through which the parent strand can determine the sequence of a new strand.

Rosalind Franklin

Dec 13, 1951

Took the famous Photo 51 and collected data eventually used by Watson and Crick. This photo indicated that DNA was a double helix, or twisted ladder shape formed by nucleotides twisted around eachother.

Hershey and Chase

Dec 13, 1952

(Afred Hershey, Martha Chase) Published results of experiments that provided evidence that DNA is a transforming factor. The figured out that viruses cannot replecate themselves, they must inject genetic material into a living cell to reproduce. They used a technique called radioactive labeling to trace the fate of the DNA and protein.

Linus Pauling

Dec 13, 1953

Created a structure of DNA series. H became intered in it when he heard Maurice Wilkins developed some good photographs of nucleic acids. Due to others creating structure models of DNA, he got a few good ideas that got him thinking about other possible structures. He created what he thinks is the correct structure.