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Lederberg in the laboratory
at the University
of Wisconsin, October 1958.
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His inquisitiveness, facility for establishing connections between scientific
disciplines, and grasp of institutional strategy led Joshua Lederberg to the forefront
of successive advances in science: molecular genetics in the 1940s and 1950s;
the search for extraterrestrial life in the 1950s and 1960s; computers and
artificial intelligence in the 1960s and 1970s. His discoveries in genetics
produced a deeper understanding not only of the biochemical mechanism of
inheritance and mutation in microorganisms, but of the evolution of diseases,
the causes of drug resistance, and the possibilities of genetic engineering
and gene therapy. |
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Edmund B. Wilson, The Cell in Development and Heredity.
3rd ed. (New York: Macmillan, 1925).
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This widely-used college textbook reiterated the scientific consensus of
the 1920s and 1930s that in the reproduction of bacteria and other
simple organisms, "no sexual process has thus far been made known"
(see p. 580), a consensus Lederberg set out to revise. |
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Laboratory Notebook, Yale University, 1946-1947,
p. 245 (June 19, 1946).
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In a series of innovative experiments conducted in the laboratory of his
doctoral adviser Edward L. Tatum at Yale University during the summer of 1946,
Lederberg demonstrated that strains of the bacterium Escherichia coli could
inherit traits from parent strains through the recombination of their
DNA. In his laboratory notes Lederberg used plus and minus signs to
mark the ability or inability of various strains of E. coli to metabolize
different nutrients, an inherited trait. Note Lederberg's declamation,
"hooray," at the occurrence of an expected result.
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E. L. Tatum and Joshua Lederberg,
"Gene Recombination in the Bacterium
Escherichia Coli," Journal of Bacteriology, vol. 53, no. 6
(June 1947): 673-684.
Click here to view
the full article.
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This article announced Lederberg's and Tatum's finding that bacteria
are complex organisms that have distinct sexual characteristics and can
reproduce through a process of genetic recombination. This conclusion
overturned the prevailing assumption that bacteria reproduced solely
through the asexual process of cell division.
With his graduate student Norton Zinder Lederberg later also found that viruses
that infect bacteria are capable of extracting genetic material from their hosts
and carrying it into other hosts. This form of genetic exchange among bacteria
by means of bacterial viruses,
which Lederberg termed viral transduction, suggested that DNA could be
deliberately manipulated and reconfigured, and thus provided the basis of
genetic engineering.
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Nobel Prize Diploma, 1958.
Original at the Rockefeller Archives Center
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The Nobel Foundation cited Lederberg, at age 33, for "his discoveries
concerning genetic recombination and the organization of the genetic
material of bacteria." He shared the prize with Edward L. Tatum
and George W. Beadle. |
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Nobel Prize medal, 1958.
Original at the Rockefeller Archives Center.
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