Editing James Watson (section)

===Luria, Delbrück, and the Phage Group===
Originally, Watson was drawn into molecular biology by the work of [[Salvador Luria]]. Luria eventually shared the 1969 Nobel Prize in Physiology or Medicine for his work on the [[Luria–Delbrück experiment]], which concerned the nature of genetic [[mutation]]s. He was part of a distributed group of researchers who were making use of the [[virus]]es that infect [[bacteria]], called [[bacteriophage]]s. He 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 PhD research in Luria's laboratory at Indiana University.<ref name="watsonphd"/> That spring, he met Delbrück first in Luria's apartment and again that summer during Watson's first trip to the Cold Spring Harbor Laboratory.<ref name=AuthorPage>{{cite book|last2=Berry|first1=James D.|last1=Watson|first2=Andrew|title=DNA : the secret of life|year=2003|publisher=Knopf|location=New York|isbn=978-0375415463|url=https://archive.org/details/dnasecretoflife00wats|edition=1st}}</ref><ref name="Luria">{{cite web|url=http://www.cshl.edu/gradschool/Non-Research-Faculty/james-d-watson |title=James D. Watson Chancellor Emeritus |access-date=December 5, 2013 |last=Watson |first=James D. |year=2012 |publisher=Cold Spring Harbor Laboratory |url-status=dead |archive-url=https://web.archive.org/web/20131211150032/http://www.cshl.edu/gradschool/Non-Research-Faculty/james-d-watson |archive-date=December 11, 2013}}</ref>

The Phage Group was the intellectual medium where Watson became a working scientist. Importantly, the members of the Phage Group sensed 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 genes were [[protein]]s and able to replicate themselves.<ref>{{Cite book|last=Putnum |first=Frank W. |title=Biographical Memoirs – Felix Haurowitz|url=http://books.nap.edu/openbook.php?record_id=4547&page=144 |edition=volume 64 |year=1994 |publisher=The National Academies Press |location=Washington, D.C. |isbn=0-309-06978-5 |pages=134–163 |quote=Among [Haurowitz's] students was Jim Watson, then a graduate student of Luria.}}</ref> The other major molecular component of [[chromosome]]s, DNA, was widely considered to be a "stupid tetranucleotide", serving only a structural role to support the proteins.<ref name=Stewart>{{cite book |last1=Stewart |first1=Ian |author-link1=Ian Stewart (mathematician) |title=The Mathematics of Life |url=https://archive.org/details/mathematicslife00stew_563 |url-access=limited |year=2011 |publisher=Basic Books |isbn=978-0-465-02238-0 |page=[https://archive.org/details/mathematicslife00stew_563/page/n13 5] |chapter=The structure of DNA}}</ref> Even at this early time, Watson, under the influence of the Phage Group, was aware of the [[Avery–MacLeod–McCarty experiment]], which suggested that DNA was the genetic molecule. Watson's research project involved using [[X-ray]]s to inactivate bacterial viruses.<ref>{{cite journal | last1 = Watson | first1 = J. D. | year = 1950 | title = The properties of x-ray inactivated bacteriophage. I. Inactivation by direct effect | journal = Journal of Bacteriology | volume = 60 | issue = 6 | pages = 697–718 | pmid = 14824063 | pmc = 385941 | doi = 10.1128/JB.60.6.697-718.1950}}</ref>

Watson then went to [[Copenhagen University]] in September 1950 for a year of postdoctoral research, first heading to the laboratory of biochemist [[Herman Kalckar]].<ref name="The Nobel Foundation"/> Kalckar was interested in the enzymatic synthesis of nucleic acids, and he wanted to use phages as an experimental system. Watson wanted to explore the structure of DNA, and his interests did not coincide with Kalckar's.<ref name="mcelheny"/> After working part of the year with Kalckar, Watson spent the remainder of his time in Copenhagen conducting experiments with microbial physiologist Ole Maaløe, then a member of the Phage Group.<ref>{{Cite journal
| last1 = Putnam | first1 = F. W.
| title = Growing up in the golden age of protein chemistry
| doi = 10.1002/pro.5560020919
| journal = Protein Science
| volume = 2
| issue = 9
| pages = 1536–1542
| year = 1993
| pmid = 8401238
| pmc =2142464
}}</ref>

The experiments, which Watson had learned of during the previous summer's Cold Spring Harbor phage conference, included the use of radioactive phosphate as a tracer to determine which molecular components of phage particles actually infect the target bacteria during viral infection.<ref name="mcelheny">{{Cite book|last=McElheny |first=Victor K. |title=Watson and DNA: Making a Scientific Revolution |year=2004 |publisher=Basic Books |isbn=0-7382-0866-3 |page=28}}</ref> The intention was to determine whether protein or DNA was the genetic material, but upon consultation with Max Delbrück,<ref name="mcelheny"/> they determined that their results were inconclusive and could not specifically identify the newly labeled molecules as DNA.<ref>{{Cite journal
| last1 = Maaløe | first1 = O.
| last2 = Watson | first2 = J. D.
| title = The Transfer of Radioactive Phosphorus from Parental to Progeny Phage
| journal = Proceedings of the National Academy of Sciences of the United States of America
| volume = 37
| issue = 8
| pages = 507–513
| year = 1951
| pmid = 16578386
| pmc = 1063410
 | doi=10.1073/pnas.37.8.507
|bibcode = 1951PNAS...37..507M | doi-access = free
}}</ref> 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 X-ray diffraction data for DNA.<ref name="The Nobel Foundation"/> Watson was now certain that DNA had a definite molecular structure that could be elucidated.<ref>{{cite book|last=Judson|first=Horace Freeland|title=The eighth day of creation: makers of the revolution in biology|chapter-url=https://archive.org/details/eighthdayofcreat00juds_1|chapter-url-access=registration|year=1979|publisher=Simon and Schuster|location=New York|isbn=0-671-22540-5|edition=1st Touchstone|chapter=2}}</ref>

In 1951, the chemist [[Linus Pauling]] in California published his model of the amino acid [[alpha helix]], a result that grew out of Pauling's efforts in [[X-ray crystallography]] and molecular model building. After obtaining some results from his phage and other experimental research<ref>{{cite web|url=http://archives.cshl.edu/R/GNCJKTHBM7E7M3ALB43BLV2SNXC2GKHNKYU5M3HIX5Q985CBKY-00055?func=collections-result&collection_id=1302|title=PDS SSO|access-date=June 29, 2015|archive-date=February 24, 2021|archive-url=https://web.archive.org/web/20210224015407/http://archives.cshl.edu/R/GNCJKTHBM7E7M3ALB43BLV2SNXC2GKHNKYU5M3HIX5Q985CBKY-00055?func=collections-result&collection_id=1302|url-status=dead}}</ref> conducted at Indiana University, [[Statens Serum Institut]] (Denmark), CSHL, and the [[California Institute of Technology]], Watson now had the desire to learn to perform [[X-ray diffraction]] experiments so he could work to determine the structure of DNA. That summer, Luria met [[John Kendrew]],<ref>{{Cite journal | last1 = Holmes | first1 = K. C. | doi = 10.1098/rsbm.2001.0018 | title = Sir John Cowdery Kendrew. March 24, 1917 – August 23, 1997: Elected F.R.S. 1960 | journal = [[Biographical Memoirs of Fellows of the Royal Society]] | volume = 47 | pages = 311–332 | year = 2001 | pmid = 15124647| title-link = John Kendrew | doi-access = free | hdl = 11858/00-001M-0000-0028-EC77-7 | hdl-access = free}}</ref> and he arranged for a new [[postdoctoral research]] project for Watson in England.<ref name="The Nobel Foundation"/> In 1951 Watson visited the [[Stazione Zoologica|Stazione Zoologica 'Anton Dohrn']] in [[Naples]].<ref>{{cite web|url=http://www.ilmattino.it/persone/il_nobel_watson_senza_napoli_non_avrei_scoperto_la_doppia_elica_del_dna/notizie/57385.shtml|title=Il Mattino|work=ilmattino.it|access-date=June 29, 2013|archive-date=August 18, 2022|archive-url=https://web.archive.org/web/20220818020817/https://www.ilmattino.it/persone/il_nobel_watson_senza_napoli_non_avrei_scoperto_la_doppia_elica_del_dna/notizie/57385.shtml|url-status=dead}}</ref>