Race for DNA Watson and Crick Nicolas Ramos Michael Cruz P1

James D. Watson Born in 1928, Watson acquired his Ph.D. in Zoology at the Indiana University. It was there where he became associated with the leading group of geneticists, the “Phage group.” Watson had knowledge of the Avery- MacLeod-McCarty experiment. Watson’s x-ray crystallography idea came from Maurice Wilkins, an associate of Rosalind Franklin, who showed him an image of DNA crystallized. He met Crick while working in the University of Cambridge. Despite their 12 year difference they both shared an interest about DNA.

Francis Crick Crick was born in England, grandson to a naturalist famous in his area. Crick’s studies were interrupted due to WWII. Inspired by the invention of the radar, Crick decided to go into the field of Biology. He taught himself x-ray crystallography while working on another scientific project about proteins.

X-ray Crystallography The reason for the discovery of DNA was crystallography. It is a technique where a pure crystal is put under x-rays. This causes diffraction (bending of light around objects.) This makes it possible to make an electron density map. After this one can make guesses using the rules of chemistry.

“The Experiment” With Watson having seen the elusive Photo 51 (DNA crystallized) and Crick’s self-taught knowledge of x-ray crystallography they were ready to decipher the secrets of DNA. From the x-ray image Crick could figure out multiple things about the DNA. However, there was no ‘experiment.’ It was just Watson and Crick sitting in a desk with cutouts that represented the four DNA bases and other subunits of nucleotides. They used all their previous knowledge of DNA, like Chargaff's rules (A=T, C=G) with their knowledge of chemistry and bonds to piece together the Double Helix model. They released it in a scientific journal under the title Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid

Rosalind Franklin controversy One of the leading members of the phage group, Rosalind Franklin did not receive credit or recognition when Watson and Crick published their findings. While there was no plagiarism involved, Watson and Crick did use data gathered by Franklin in their experiment. However, they did not know the data belonged to her. Photo 51 was shown to Watson by an associate of Franklin, Maurice Wilkins, who was not involved in creating the model but and denied receive co-authorship when the article was released. Franklin’s research, lectures, and seminars were also well known by Watson and Crick, which helped them in solving the puzzle. Here is a list of things Franklin contributed to Watson and Crick’s finding. 1- Found out and told Watson and Crick about B and A DNA 2- Told Watson and Crick the DNA backbone had to be on the outside 3- Her DNA image was the best available at the time

Aftermath Watson, Francis Crick, and Maurice Wilkins received the Nobel Prize of medicine Franklin lost the battle against ovary cancer in 1958 and could not be considered for the Nobel Prince. Maurice Wilkins received it instead. It is unknown if she would have received it in his place. Since her death, Franklin has been recognized and honored for her work toward achieving DNA.

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