James D. Watson

James Dewey Watson (born April 6, 1928) is one of the discoverers of the structure of the DNA molecule. Born in Chicago, he has been fascinated by birds since he was a child due to the influence of his father. At the age of 12, he starred on the Quiz Kids, a popular radio show that challenged precocious youngsters to answer difficult questions. Thanks to the liberal policy of Robert Hutchins, he enrolled at the age of 15 at the University of Chicago. After reading Erwin Schrodinger's book What Is Life? in 1946, he changed his direction from ornithology to genetics. Watson earned a B.Sc. in Zoology in 1947.

The Phage Group

Upon arriving at Indiana University at Bloomington to start graduate studies, Watson was attracted to the work of Salvador Luria. Luria eventually shared a Nobel prize for his work on the Luria-Delbruck experiment, which concerned the nature of genetic mutations. Luria was part of a distributed group of researchers who were making use of the viruses that infect bacteria in order to explore genetics. Luria and Max Delbrück were among the leaders of this new "Phage Group", an important movement of geneticists from experimental systems such as Drosophila towards microbial genetics. Early in 1948 Watson began his Ph.D. research in Luria's laboratory and that spring he got to meet Delbrück in Luria's apartment and again that summer diring Watson's first trip to the Cold Spring Harbor Laboratory. The Phage Group was the intellectual medium within which Watson became a working scientist. Importantly, the members of the Phage Group had a sense that they were on the path to discovering the physical nature of the gene. In 1949 Watson took a course with Felix Haurowitz that included the conventional view of that time: that proteins were genes and able to replicate themselves. The other major molecular component of chromosomes, DNA, was thought by many to be a "stupid tetranucleotide", serving only a structural role to support the proteins. However, even at this early time, Watson, under the influence of the Phage Gorup, was aware of the work of Oswald Avery which suggested that DNA was the genetic molecule. Watson's research project involved using X-rays to inactivate bacterial viruses ("phage"){{ref|thesis}}. He gained his Ph.D. in Zoology at Indiana University in 1950. Watson then went to Europe for postdoctoral research, first heading to the laboratory of biochemist Herman Kalckar in Copenhagen who was interested in nucleic acids and had developed an interest in phage as an experimental system.

Related Topics:
Indiana University at Bloomington - Salvador Luria - Luria-Delbruck experiment - Mutations - Virus - Bacteria - Max Delbrück - Drosophila - Cold Spring Harbor Laboratory - Gene - Protein - Chromosome - Oswald Avery - X-ray - Phage - 1950 - Biochemist - Copenhagen - Nucleic acid

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Watson's time in Copenhagen had one favorable consequence. He was able to do some experiments with Ole Maaloe (a member of the Phage Group) that were consistent with DNA being the genetic molecule. Watson had learned about these kinds of experiments the previous summer at Cold Spring Harbor. The experiements involved radioactive phosphate as a tracer and attempted to determine what molecular components of phage particles actually infect the target bacteria during viral infection. Watson never developed a constructive interaction with Kalckar, but he did accompany Kalckar to a meeting in Italy where Watson saw Maurice Wilkins talk about his X-ray diffraction data for DNA. Watson was now certain that DNA had a definite molecular structure that could be solved{{ref|Judson}}.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

In 1951 Linus Pauling published his model of the protein alpha helix, a result that grew out of Pauling's relentless efforts in X-ray crystallography and molecular model building. Watson now had the desire to learn to perform X-ray diffraction experiments so that he could work to determine the structure of DNA. That summer, Luria met John Kendrew and arranged for a new postdoctoral research project for Watson in England.

Related Topics:
Linus Pauling - Alpha helix - John Kendrew

~ ~ ~ ~ ~ ~ ~ ~ ~ ~