Tatum, Edward Lawrie WORLD OF MICROBIOLOGY AND IMMUNOLOGY542•
can make all the amino acids and vitamins it needs to live
except for one (biotin).
This is exactly what happened. In the course of their
research, the men created, with x-ray bombardment, a number
of mutated strains that each lacked the ability to produce a par-
ticular amino acid or vitamin. The first strain they identified,
after 299 attempts to determine its mutation, lacked the ability
to make vitamin B 6. By crossing this strain with a normal
strain, the offspring inherited the defect as a recessive gene
according to the inheritance patterns described by Mendel.
This proved that the mutation was a genetic defect, capable of
being passed to successive generations and causing the same
nutritional mutation in those offspring. The x-ray bombard-
ment had altered the gene governing the enzyme needed to
promote the production of vitamin B 6.
This simple experiment heralded the dawn of a new age
in biology, one in which molecular genetics would soon dom-
inate. Nearly 40 years later, on Tatum’s death, Joshua
Lederberg told the New York Timesthat this experiment “gave
impetus and morale” to scientists who strived to understand
how genes directed the processes of life. For the first time,
biologists believed that it might be possible to understand and
quantify the living cell’s processes.
Tatum and Beadle were not the first, as it turned out, to
postulate the one gene-one enzyme theory. By 1942, the work
of English physician Archibald Garrod, long ignored, had
been rediscovered. In his study of people suffering from a par-
ticular inherited enzyme deficiency, Garrod had noticed the
disease seemed to be inherited as a Mendelian recessive. This
suggested a link between one gene and one enzyme. Yet Tatum
and Beadle were the first to offer extensive experimental evi-
dence for the theory. Their use of laboratory methods, like x
rays, to create genetic mutations also introduced a powerful
tool for future experiments in biochemical genetics.
During World War II, the methods Tatum and Beadle
had developed in their work with pink bread mold were used
to produce large amounts of penicillin, another mold. In 1945,
at the end of the war, Tatum accepted an appointment at Yale
University as an associate professor of botany with the prom-
ise of establishing a program of biochemical microbiology
within that department. In 1946. Tatum did indeed create a
new program at Yale and became a professor of microbiology.
In work begun at Stanford and continued at Yale, he demon-
strated that the one gene-one enzyme theory applied to yeast
and bacteria as well as molds.
In a second fruitful collaboration, Tatum began working
with Joshua Lederberg in March 1946. Lederberg, a Columbia
University medical student 15 years younger than Tatum, was
at Yale during a break in the medical school curriculum. Tatum
and Lederberg began studying the bacterium Escherichia coli.
At that time, it was believed that E. colireproduced asexually.
The two scientists proved otherwise. When cultures of two
different mutant bacteria were mixed, a third strain, one show-
ing characteristics taken from each parent, resulted. This dis-
covery of biparental inheritance in bacteria, which Tatum
called genetic recombination, provided geneticists with a new
experimental organism. Again, Tatum’s methods had alteredthe practices of experimental biology. Lederberg never
returned to medical school, earning instead a Ph.D. from Yale.
In 1948 Tatum returned to Stanford as professor of biol-
ogy. A new administration at Stanford and its department of
biology had invited him to return in a position suited to his
expertise and ability. While in this second residence at
Stanford, Tatum helped establish the department of biochem-
istry. In 1956, he became a professor of biochemistry and head
of the department. Increasingly, Tatum’s talents were devoted
to promoting science at an administrative level. He was instru-
mental in relocating the Stanford Medical School from San
Francisco to the university campus in Palo Alto. In that year
Tatum also was divorced, then remarried in New York City.
Tatum left the West coast and took a position at the Rockefeller
Institute for Medical Research (now Rockefeller University) in
January 1957. There he continued to work through institutional
channels to support young scientists, and served on various
national committees. Unlike some other administrators, he
emphasized nurturing individual investigators rather than spe-
cific kinds of projects. His own research continued in efforts to
understand the genetics of Neurosporaand the nucleic acid
metabolismof mammalian cells in culture.
In 1958, together with Beadle and Lederberg, Tatum
received the Nobel Prize in physiology or medicine. The
Nobel Committee awarded the prize to the three investigators
for their work demonstrating that genes regulate the chemical
processes of the cell. Tatum and Beadle shared one-half the
prize and Lederberg received the other half for work done sep-
arately from Tatum. Lederberg later paid tribute to Tatum for
his role in Lederberg’s decision to study the effects of x-ray-
induced mutation. In his Nobel lecture, Tatum predicted that
“with real understanding of the roles of heredity and environ-
ment, together with the consequent improvement in man’s
physical capacities and greater freedom from physical disease,
will come an improvement in his approach to, and under-
standing of, sociological and economic problems.”
Tatum’s second wife, Viola, died in 1974. Tatum mar-
ried Elsie Bergland later in 1974 and she survived his death
the following year, in 1975. Tatum died at his home on East
Sixty-third Street in New York City after an extended illness,
at age 65.See alsoFungal genetics; Microbial genetics; Molecular biology
and molecular genetics; Molecular biology, central dogma ofTECHNOLOGY AND TECHNIQUES IN
IDENTIFICATION OF MICROORGANISMS•
seeGENETIC IDENTIFICATION OF MICROORGANISMSTEM•seeELECTRON MICROSCOPE, TRANSMISSION AND
SCANNINGTERRORISM, USE OF MICROBIOLOGICAL
AGENTS•seeBIOTERRORISMwomi_T 5/7/03 11:02 AM Page 542