a

ultra viclet kei rr

as a result of exposure to UF and had thus become sensitive to reinfection.
(Prophages, especially noninducible or defective ones, often turn up in well-
known strains of bacteria.)

Owing to the work of Lwoff and Bertani (Chapter 6), temperate phages were
already subjects of renewed interest in 1951. When Lederberg and Lederberg
(1953) found that A prophage segregates with certain bacterial genes (gal) in
crosses between lysogenic and nonlysogenic bacteria, interest quickened. Here
was the first clue to what had always seemed a contradiction in terms: hereditary
transmission of a virus from cell to cell. Ten years of intensive work were
needed before bacterial crosses in general, and Agal linkage in particular,
could be understood. Eventually it was shown that A prophage is inserted into
the bacterial chromosome between gal and bio by a locus-specific and phage-
specific mechanism of genetic recombination (Chapter 6). The prophage location,
together with another novel kind of genetic recombination, also account for the
propensity of A to form transducing phages that disseminate gal and bio genes
among bacteria (Chapter 8). |

Historical matters are dealt with by Stent (1963) and Campbell (1969),
and in the various chapters of this book. In the bibliography of this chapteér we

Section |

list as a separate chapter some unselected early publications concerning A.
Tae unnretouchec( Aecened

Their titles present am-anfiltered histex; of how it all started.

Taxonomy

Lambda is one of a number of naturally occurring phages that have three
properties in common: they recombine when crossed with one another, their DNA.
molecules terminate in similar or identical nucleotide sequences (Chapter 5),

and their prophages are inducible by ultraviolet irradiation. The known members
Memo from To: Al H.
JOSHUA LEDERBERG

JUL 15 7

Lambda history |

 

_ I have nothing to criticizés (or I would.
doubtless have answered sooner.)

 

I should Say that it was s BURNET's _ work,
above all, that had sensitized me to the genetic
interest inherent in lysogenicity,

~~~~Note,~ for example, the itnctuston of ~~~

Burnet-& Lush (Austrat-J3-Exp Biol —14127- 1936) in,
my 1951 cottection of +Papers in Microbtal- Genetics
andthe ‘passing remarks thereon tn the introduct-
fons a

_ __Perhaps your Chap. 6 makes all necessary -
(4f any) allusiaons to the incunabula.  _—s_

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

~ PROFESSOR JOSHUA LEDERBERG
x Department of Genetics
School of Medicine
Stanford University
Stanford, California 94305