June 16, 1952

REPORT ON RESEAT-CH PROJECTS

 

 

Yor the
FICCAL YEAR 1951-52
I. Name WMDERBERG J. Dept, GENETICS Proj, No. 328308
Title Bacterial Genetics
Il. Personnel: Elise Caha (now transferred to another dept.)
eeonne Bthelyn Lively (part)
Phyllis Fried feraduated, M.A. 1952)
Norton Zinder (part) graduated, BhaD. 1952)

III. Statement of other financial support, if any:
tomic Ehergy Commission $ 1500
National Institutes of Health $ 4320
Auny Chemical Corps ca $ 5000 (prorated for '51-52)
IV. Brief statemtnt of specific progress made during the year:

Genetic recombination in Salmonella has been found to take place by a new mecha-
nism. Virus particles grown on one strain may transfer genetic material (chromosomal
fragments) to another. New types of Salmonella have been synthesized by hybridizing
S. typhi X A. typhiouriun.

In nerichia coli, ganetic factors which control sexual compatibility have
been discovered, making it possible to control crosses, and to achieve mich higher
frequencies of sexual mating. So far, no cytological correlate of mating has been
found, suggesting thet this 4s a simple process uncomplicated by any special fruiting
structures as clsimed by cther workers. The chromosomal oschanism has been further
clarified, but 4s still quite complex. However, there are probably two, rather than
just one chromosome.

Lysogenteity (latent virus growth) has been studisd by orcasing methods. A single
chromosomal gene controls the growth of the virua. It is reasonably probable that the
virus is actually fixed on the chromosome while it is latent. This is further evidence
for sn especially close relationship between virus growth and cuclear functiog.

A new method (replica plating) has been developed for handling large numbers of
bacterial clones, and has been applied to a rigorous proof that adeptive mtations of
bacterta are spontansous, and aelacted by the environrent.

V. Publications that have appeared in print during the present fiscal year:
Lederberg,J., Prevalence of Escherichia coli strains exhibiting genetic recombination.

Selence 114: 68, 1951 (July
Lederberg, J.» ant 1951 (ouly) ; Replica plating and indirect selection of bacterial

mitants. J. Bast. 63:399, 1952 (March)
Ledergerg,J., Lederberg,E.M., Zinder..D. and Lively,E.R., Recombination analysis of
bacterial heredity. Cold Spring Harbor Symposia Quant. Bicol. i6: 413, 1951

VI. Menuseripts eecepted for publication but not yet printed:
Lederberg,J., Cavdli,L.L., ant Lederberg.2.M., Sax compatibility in Fscherichia coli.
Genetics, In Press.
Zinder, N.D.,and Lederberg,J., Genetic exchange in Salmonella. J. Bact., In Bress
Lederberg,J.? Soma biologéoal aspects of bacterial genetics. Proc. 21 Natl. Cancer Cong.
In Press
Lederberg,£.M.,and Lederberg,J.°Genetic st&dies of lysogenicity in Escherichia colt.
Genetics, In Press
The pink copy should be returned _to the Graduate School Office on or herore

August 1, 1952. The blue copy is for your File.
netics 6 6 cats . Physiol. Rev., In Press
Lederberg, J.’ ge ?