THE ROCKEFELLER INSTITUTE FOR MEDICAL RESEARCH

66TH STREET AND YORK AVENUE
NEW YORK @I,N_Y.

March 6,1955

Dr. Joshua Lederberg
Dept of Genetics
University of kisconsin
Madison, Wisc.

Dear Joshua:

Since I received your letter I have spoken to Alan and he told me that he
had written to you amt that he had changed his mind about going to wisconsin, so
there is nothing further I might add. ,

I've met itiss Thomas and she's asked me about Wisconsin, Since she is only
a beginning graduate student Ja assume you are interested ink her personality
rather tahn any scientific achievment. I have found her a very pieant pleasing
person and well adjusted. She has very little in the awy of academic background
but seems willing and able to learn, I'm not sure what you mean by"fit in" but
if it refers to being troublesome I would tend to doubt it,

I have intended to write ydu in detail about some of the work that Alan
and I have been doing but every time I tried it started to turn into a manuscript,
As Alan mentioned we have been attempting to write things up and as usual this turned
out to be a most enlightening experihce in separating fact from fancy and so we are
back in the laboratory mmkintx giving some basis in fact for some wilder speculation.
In essence what we are trying to show is that the genetic material of bacteriophage
has homologous material in the sensitive non-lysogenia bacterium and that
lysogenization may be only an allelic shift or at best the addition (non-substitutivwe )
of a small fragment. We tried to show this) solely +a radiological means but this
was only supportive and not conclusive,so we are now looking for direct evidence
of bacterial and phage recombination. Believe it or,not it looks as if we just fell
into some, Since everything hinges upon the different connotations of the same
words I shan't endeavor to explain at this time. Rutn Cager mentioned your coming
to NY some time this spring I hope to see you then and we can have a good dikcussion.

The only xaumm reason I wanted a gal- that gave stable transducions was
that 1 feared the unstable might be insufficient fem for detigled quantitation.
Papillate selection seems pretty good in most cases I have studied but I've
nver looked at one continually segregating and I was afraid one might lose
transductions for rather trivial reasons with unstable systems (medium differences éc),
The simple straight forward experidmt is exactly what I intend to try with
a slight variation, A small dose of UV to the host to mitigate lysogenization and
get complete lysis. My memx own hunch is that it won't wobk in systems that
show already lytic activity but then I have different preconceptions, Upon
receipt of the stocks will try it both with Salmonella and coli,

I do not have any coli stocks and although I might have gotten them from
CSH I preferred to get them from you so that you both knew that I had thems and
also had some idea what I was going to do with them.

Regards to all;
Yours sincerely,

hen