Brenner, Sydney WORLD OF MICROBIOLOGY AND IMMUNOLOGY86•
Pittsburgh he earned an M.S. in 1960 and a Ph.D. in bacteriol-
ogy in 1963. In 1966 Boyer joined the biochemistryand bio-
physics faculty at the University of California, San Francisco,
where he continues his research.
Boyer performed his work with Stanley Cohen from the
Stanford School of Medicine and other colleagues from both
Stanford and the University of California, San Francisco. The
scientists began by isolating a plasmid (circular DNA) from
the bacteriaE. colithat contains genes for an antibiotic resist-
ancefactor. They next constructed a new plasmid in the labo-
ratory by cutting that plasmid with restriction endonucleases
(enzymes) and joining it with fragments of other plasmids.
After inserting the engineered plasmid into E. colibac-
teria, the scientists demonstrated that it possessed the DNA
nucleotide sequences and genetic functions of both original
plasmid fragments. They recognized that the method allowed
bacterial plasmidsto replicate even though sequences from
completely different types of cells had been spliced into them.
Boyer and his colleagues demonstrated this by cloning
DNA from one bacteria species to another and also cloning
animal genes in E. coli.
Boyer is a co-founder of the genetic engineering firm
Genentech, Inc. and a member National Academy of
Sciences. His many honors include the Albert and Mary
Lasker Basic Medical Research Award in 1980, the National
Medal of Technology in 1989, and the National Medal of
Science in 1990.See alsoMolecular biology and molecular geneticsBBrenner, Sydney RENNER, SYDNEY(1927- )
South African–English molecular biologistSydney Brenner is a geneticist and molecular biologist who
has worked in the laboratories of Cambridge University since- Brenner played an integral part in the discovery and
understanding of the triplet genetic codeof DNA. He was also
a member of the first scientific team to introduce messenger
RNA, helping to explain the mechanism by which genetic
information is transferred from DNA to the production of pro-
teins and enzymes. In later years, Brenner conducted a mas-
sive, award-winning research project, diagramming the
nervous system of a particular species of worm and attempting
to map its entire genome.
Brenner was born in Germiston, South Africa. His par-
ents were neither British nor South African—Morris Brenner
was a Lithuanian exile who worked as a cobbler, and Lena
Blacher Brenner was a Russian immigrant. Sydney Brenner
grew up in his native town, attending Germiston High School.
At the age of fifteen, he won an academic scholarship to the
University of the Witwatersrand in Johannesburg, where he
earned a master’s degree in medical biology in 1947. In 1951,
Brenner received his bachelor’s degree in medicine, the qual-
ifying degree for practicing physicians in Britain and many of
its colonies. The South African university system could offer
him no further education, so he embarked on independent
research. Brenner studied chromosomes, cell structure, and
staining techniques, built his own centrifuge, and laid the
foundation for his interest in molecular biology.
Frustrated by lack of resources and eager to pursue his
interest in molecular biology, Brenner decided to seek educa-
tion elsewhere, and was encouraged by colleagues to contact
Cyril Hinshelwood, professor of physical chemistry at Oxford
University. In 1952, Hinshelwood accepted Brenner as a doc-
toral candidate and put him to work studying a bacteriophage,
a virus that had become the organism of choice for studying
molecular biology in living systems. Brenner’s change of
location was an important boost to his career; while at Oxford
he met Seymour Benzer, with whom Brenner collaborated on
important research into genemapping, sequencing, mutations
and colinearity. He also met and exchanged ideas with James
Watsonand Francis Crick, the Cambridge duo who published
the first paper elucidating the structure of DNA, or deoxyri-
bonucleic acid, the basic genetic molecule. Brenner and Crick
were to become the two most important figures in determining
the general nature of the genetic code.
Brenner earned his Ph.D. from Oxford in 1954, while
still involved in breakthrough research in molecular biology.
His colleagues tried to find a job for him in England, but he
accepted a position as lecturer in physiology at the University
of the Witwatersrand and returned to South Africa in 1955.
Brenner immediately set up a laboratory in Johannesburg to
continue his phage research, but missed the resources he had
enjoyed while in England. Enduring almost three years of iso-
lation, Brenner maintained contact with his colleagues by mail.
In January 1957, Brenner was appointed to the staff of
the Medical Research Council’s Laboratory of Molecular
Biology at Cambridge, and he and his family were able to set-
tle in England permanently. Brenner immediately attended to
theoretical research on the characteristics of the genetic code
that he had begun in Johannesburg, despite the chaotic atmo-
sphere. At the time, the world’s foremost geneticists and
molecular biologists were debating about the manner in which
the sequences of DNA’s four nucleotide bases were interpreted
by an organism. The structure of a DNA molecule is a long,
two-stranded chain that resembles a twisted ladder. The sides
of the ladder are formed by alternating phosphate and sugar
groups. The nucleotide bases adenine, guanine, thymine, and
cytosine—or A, G, T, and C—form the rungs, a single base
anchored to a sugar on one side of the ladder and linked by
hydrogen bonds to a base similarly anchored on the other side.
Adenine bonds only with thymine and guanine only with cyto-
sine, and this complementarity is what makes it possible to
replicate DNA. Most believed that the bases down the rungs
of the ladder were read three at a time, in triplets such as ACG,
CAA, and so forth. These triplets were also called codons, a
term coined by Brenner. Each codon represented an amino
acid, and the amino acids were strung together to construct a
protein. The problem was in understanding how the body
knew where to start reading; for example, the sequence AAC-
CGGTT could be read in several sets of three-letter sequences.
If the code were overlapping, it could be read AAC, ACC,
CCG, and so forth.
Brenner’s contribution was his simple theoretical proof
that the base triplets must be read one after another and couldwomi_B 5/6/03 1:10 PM Page 86