CARNEGIE INSTITUTION OF WASHINGTON

DEPARTMENT OF GENETICS

COLD SPRING HARBOR, LONG ISLAND, N. Y.

Sept. ll, 1956

Dr. Joshua Lederberg
Department of Genetics
University of Wiscongin
Madison, Wisconsin

Dear Josh:

I would greatly appreciate your sending me strains
of E. coli with diverse origins. You must have 18ts of
these strains around from your studies of the distribution
of sexuality.

I want to isolate strains which adsorb T8 and
from these I want to select: 1) /2 mutants which
adsorb D.at a faster rate than my B/2 which is pretty
poor. 2) /2 mutants with which I c select h s¥stems
differ nt from those formed in resifise to B/E,

If you have strains which you know adsorb
T2L would it be possible to send 15 or twenty
strains, otherwise 40 or 50 strains? I realize that
this is asking quite a lot, and that a great deal of
labor on your part is involved. I would be very
grateful however for anything that you may be able to
send. I am anxious to get a variety of strains;
different K-12 derivatives etc. would probably not
differ very much in their adsorptive capacities.

Thank you very much for anything that you may
be able to do along these lines.

With best regards to you and Esther,
Very sincerely,

George Streisinger