THE DISCOVERY OF THE DOUBLE HELICAL STRUCTURE OF DNA, 1953 term paper

In the early 1950s one of the major scientific questions concerned the structure of DNA (deoxyribonucleic acid). DNA molecules, present in the chromosomes of all plant and animal cells, were thought to contain instructions for passing on hereditary characteristics and for the functions of cells. Learning more about their structure would be a scientific breakthrough of immense significance.

The breakthrough came in 1953 as a result of the efforts of two somewhat unorthodox scientific investigators, Francis Crick and James Watson. Crick was a British biophysicist working at the Cavendish Laboratory at Cambridge University. In 1951 he met and became friends with James Watson, a former Quiz Kid on the radio who received a Ph.D. in genetics from Indiana University at age twenty-two. The two were supposed to be working on other projects, but kept coming back to the idea that a model of the structure of the DNA molecule was the key to several important questions.

In the early 1950s the investigator closest to the secret of the structure of DNA was Rosalind Franklin, a brilliant physical chemist who had been working on X-ray crystallography methods in Paris. In 1951 she joined a research unit at King’s College, London. Unfortunately, she and a member of the research unit who had been working on X-ray diffraction of DNA, Maurice Wilkins, got off to a bad start and never worked together effectively.

It was a lecture by Franklin in 1951 that sent Watson and Crick off to build their first model of DNA. Watson had heard the lecture but had not taken notes. Franklin later viewed the model and subjected it to a devastating critique. Crick and Watson were actually banned from working on DNA afterwards by the head of the Cavendish Laboratory.

In America, Linus Pauling, a physical chemist who had constructed the first satisfactory model of a protein molecule, came very close to determining the structure of DNA in a paper he published in January 1953. Watson obtained a copy of the paper and knew that Pauling might soon be the first to publish a paper on the structure of DNA. Watson was aided by Wilkins, who showed him one of Franklin’s X-ray photographs, without her knowledge or consent. Watson also obtained data presented by Franklin to a departmental seminar. Crick realized that Franklin’s data suggested an antiparallel double helix structure (a slightly twisted ladder the rungs of which are composed of pairs of nitrogen-containing nucleotides, which allows half of the molecule to serve as a template for the construction of the other half). Crick and Watson published a paper in the British journal Nature on 18 March 1953. Only the day before, Franklin had drafted a paper that spelled out most of the structure, but priority of publication was what counted. In 1962 Watson, Crick, and Wilkins received the Nobel Prize in Physiology or Medicine. Franklin had died of cancer in 1958. Had she lived, she undoubtedly would have shared in the Nobel Prize she had inadvertently done so much to make possible.
Suggestions for Term Papers
1. Write a paper on what was known in the early 1950s about genes.
2. Compare the account of the discovery of the structure of DNA presented by James Watson in The Double Helix with that of Crick and of historians.
3. Investigate the life of Rosalind Franklin, a key figure in the search for the structure of DNA, and write a paper on her as scientist and as woman.
4. Follow James Watson’s career after he and Crick discovered the structure of DNA. To what extent has his career fulfilled the extraordinary promise that he showed in his early twenties?
5. Develop a time line that traces the developments coming after Crick and Watson discovered the structure of DNA. Use the cloning of Dolly the sheep in 1997 as a cutoff point. Books by Lee M. Silver and by Necia Grant Cooper will be useful (see Suggested Sources).

Research Suggestions

In addition to the boldfaced items, look under the entries for “The ‘Green Revolution’ in Agriculture in the 1960s” (#61), “First ‘TestTube’ Baby Born, 1978” (#79), and “Dolly the Sheep Cloned, 1997” (#96). Search under Recombinant DNA, DNA Sequencing, Human Genome Project, and Cloning.

SUGGESTED SOURCES

Primary Sources

Crick, Francis. Of Molecules and Men. Seattle: University of Washington Press. 1966. A discussion of some of the implications of the revolution in molecular biology.

———. What Mad Pursuit: A Personal View of Scientific Discovery.New York: Basic Books. 1988. Crick’s account of the work he and James Watson carried out.

Watson, James. The Double Helix: A Personal Account of the Discovery of the Structure of DNA. New York: Athenaeum, 1968. Also published as a Norton Critical Edition in 1980. One of the best known twentienth-century accounts of scientific discovery.

Secondary Sources

Cooper, Necia Grant, ed. The Human Genome Project: Deciphering the Blueprint of Heredity. Mill Valley, Ca.: University Science Books, 1994. Useful overviews of progress in genetic research since Crick and Watson.

Gribbin, John. In Search of the Double Helix: Quantum Physics and Life. New York: McGraw-Hill. 1985. An excellent introduction.

Judson, Horace Freeland. The Eighth Day of Creation: The Makers of the Revolution in Biology. Expanded ed. Plainview, N.Y.: Cold Spring Harbor Laboratory Press, 1996. A good discussion of the discovery of the structure of DNA.

Licking, Ellen F. “Double-Teaming the Double Helix.” U.S. News&World Report, 17 August 1998, 72–73. An excellent overview.

Sayre, Ann. Rosalind Franklin and DNA. New York: W. W. Norton, 1975. Dr. Franklin’s work was vital to the success of Crick and Watson. Unfortunately, her death from cancer in 1958 meant she did not share the Nobel Prize with them.

Silver, Lee M. Remaking Eden: How Genetic Engineering and Cloning Will Transform the American Family. New York: Avon, 1998. This edition contains an afterword. Silver, a molecular biologist at Princeton, provides a popular and solid discussion of genetics and gene manipulation.