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Week’s Citation Classic
Bachmann B i, Low K B & Taylor A L. Recalibrated linkage map of
FEBRUARY22,1982
Escherichia coli K-12. Bacteriol. Rev. 40:116-67, 1976.
[Yale Univ. School of Medicine, New Haven, CT and Univ. Colorado
Medical Center, Denver, COJ
and came to Yale to help in the analysis
of the data.
“First, Brooks Low recalibrated the
map, which is still based on the time-ofentry of markers by conjugation, using
the large set of Hfr strains which he had
assembled—and many of which he had
isolated. To our surprise and delight,
the result was a 100-minute map (which
is so convenient a figure that some
have assumed that this length was
Barbara J. Bachmann
chosen arbitrarily). This map paper conDepartment of Human Genetics
tained around 680 gene loci and a bibliYale University School of Medicine
ography of 763 citations. Obviously,
New Haven, CT 06510
not every person using E. co/i could afford to perform this synthesis for
himself. It is the drawing, the bibliogOctober 27, 1981
raphy, and the table of gene functions
that are most often used. Apparently,
“The series of linkage maps of few people read the text, which conEscherichia co/i K-12 was begun by A.L.
tains many qualifications and exhorts
Taylor in 19641 and has served since as the reader to consult the original
an essential tool in experimental work
literature.
directed toward understanding the
“1 later came to appreciate Taylor’s
genome of this organism. Early editions
many reasons for wishing to relinquish
of the ‘map paper’ presented extensive this task. Each time the map is drawn it
mapping data from Taylor’s laboratory.
is necessary to go over all data ever
in addition to providing syntheses of all
published and to reconcile the widely
published data, a standardized system varying, and sometimes conflicting,
of nomenclature, a list of gene func- results obtained in different laboratotions, and a graphic representation of
ries. It is also necessary to arbitrate
the chromosome. By 1972,2 the number disputes regarding gene symbols. Conof gene loci on the map had increased
structing the map is one way to offend
from 100 to 460. As explorations in a great many people simultaneously.
molecular biology came to be focused When the entire map is fitted together.
to a large extent on this one organism,
almost no gene is put exactly where
the map paper became essential to
any one person said it was and the posimany who were not primarily microbial tion is seldom precisely known.
geneticists.
“I revised the map again in 1980,~
“In 1975, another revision of the map with the generous assistance of a great.
was badly needed and Taylor realized many of the authors of the data, and
that he could not spare the time re- Low contributed a review of mapping
quired to continue the series. It seemed
techniques. The number of gene loci
reasonable for me to take over the re- mapped has continued to increase linview because, as curator of the E. co/i early with time. The 1980 edition conGenetic Stock Center. I need to keep tains almost 1,000 loci, representing
track of all of the loci on the map in possibly close to one quarter of the
order to respond to requests for strains. genes of the best known of all
Taylor agreed to assist with this edition, organisms.”
L
This paper presents a critical review of all
data on the linkage of genes on the Escherichia co/i K-12 chromosome, a list of genes
and their functions, and a graphic representation of the circular chromosome. [The
SCI® indicates that this paper has been cited
over 1,185 times since 1976.)
-
1. Taylor A L I Thomas M S. The genetic map of Esch.nchia coli K-I2. Genetic, 50:659-77,1964. The SC! indicates that thin paper ban been cited over 205 times sInce 1964.1
2. Taylor A L I Trotter C D. Linkage map of Eschenchw coli strain K-12. Bactenol. Rev. 36504-24. 1972.
(The SC! indicaten that this paper ban bcen cited over 665 times since 1972.)
3. Bachmw B 1 & Lo~w~ B. U~kagemap of Eschencltia coil 1(42, edition 6.
Microbioi. Rev. 44:1-56, 1980. (The SC! indicates that this paper baa been cited over 200 tImes sInce 1980.1
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