University oF MINNESOTA

Tue Mepicat Scuoou
Minweaporis 14

DEPARTMENT OF BACTERIOLOGY Mar ch 6 ’ 1 9 59
AND IMMUNOLOGY

Doctor Joshua Lederberg, Head
Department of Medical Genetics
Stanford University Medical School
Palo Alto, California

Dear Josh:

I gather from Dennis Watson that you survived subculture with a high efficiency-of-plating
and that progress has begun without an appreciable lag phase. I woutd if the close proximity
of biochemists will be mutagenic or selective. With the primary heterogenotes in
California, and numerous exogenotes such as Zinder in New York, Morse in Colorado, and
Wright in Australia, you should be subject easily to global transduction,

As you know, I have recently received inquiries concerning positions at Cornell, Western
Reserve and Duke. The latter I declined immediately on the basis of integration problems
there. I am not willing to run the risk of cancelled public schools, etc. i have visited
Cornell and Western Reserve. Both made financially attractive offers and had seperior
laboratory facilitiesatd my present situation, Fora vayiety of reasons, I have decided not
to accept either.offer. I have been attemptingjevaluatimesef my position here with respect to
facilities, scientific opportunity and academic atmosphere. My views remain the same as
expressed previously.

I received your note and the NSF application today. I went over it and have sent off my
appraisal.

Our own work progresses well, rme-ver as rapid as I would hope. I was away on the trip-to
Cornell and Western Reserve; I still haven't caught up. My problems in this respect must be
small compared to yours,

The reciprocal crosses, in our hands, yield identical results:

A-Y® x B-Y® ----- > A+BtyY®
A-Y "x B-Y 7----- > A+Bity™
5 : where A+B+ are selected
A-Y x B-Y®----- > A+BtY
A-Y° x B-Y" ----- > A+Btry §

A and Bare nutritional markers; Y represents phage or ste eptomycin susceptibility.
Dr. Joshua Lederberg
Page 2
March 6, 1959

If we select for presumably recessive markers, the results are more interesting:

| ) A-Bt

A-X8 y* + B-XT Y5 -_--—>hemt ee xt y ( A+B-
) A-B-

( A+Bt

By this procedure, we are avoiding the "heterokaryon" amd getting directly to the "gene
redombinant''". There still are some unusual aspects of nuclear behavior in this organism,

I should write more, but I need to get to other things. Also, I realize that you have much to
do. My very best wishes to you and Esther,

Sincerely,

  

SGB:ch s. Gaylen Bradley 4 itt ‘
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