THE UNIVERSITY OF WISCONSIN
MADISON, WISCONSIN, U.S. A.

DEPARTMENT OF BOTANY
BIOLOGY BUILDING

October 12,1946

Mr.Joshua 4ederberg

Osborn Botanical Laboratory
Yale University

New Haven , Conn.

My Dear Mr.Lederberg,

I have before me a request for some of my reprints by you , dated
February 1945, I believe that, being always on the move, I have neglected
to fill that request. I am therefore sending you now under separate cover
the second paper you asked for, the first one no longer being available.

I hope you will forgive me and comply with a request I have to make of
you more speedily thah I did with yours.

I was very much interested in the data you gave at the Cold Spring
Harbor Symposium and have promised to give a short eeminar talk here,
on the subject of "Sex and seggregation in bacteria". I have only very
scetchy notes from the meeting to go by since I have not yet seen your
material in print. Put me straight if I'm wrong. If your data have
not yet appeared would you be so kind as to check, correct and supple-
ment the enclosed notes, and send them back to me. Particularly I should
like to know what the B,M,P,T designations stand for, any figures or
numbers that you may have. If you have found contradictory evidence
in the meantime , I should very much like to have that too. I hope
you will answer me promptly and put my name on your mailing list forn
the forthcoming paper.

I also hope to get a chance to talk further with you if you

are going to attend the AAAS meetings in Boston at Xmas.

fw Cine rrrannpeurp Yours sincerely
L 1b —— Athy: vu,

Lotti M.Steinitz “
Some Evidence for Sex and Seggregation in Bacteria.

Discussion at the Cold Spring Harbor Symposium 1946 by Joshua Lederberg.

Working with mutant strains of E.coli found spontaneous reapnearance of
the wild type only once in 10 000 000. (7)

Starting with certain mutants (which 7?)

he made mixed cultures of two double mutants (BrM=P?T+)and (BtMtP-T-)
The wild type appeared in these mixed cultures. On isolation it was
possible to obtain lines that were homogeneous for all (7?) possible
combinations of the characters involved.

No single snore isolations were made, but the serial dilution technique
was used, which insures with a high degree of certainty that the zsolates
no longer consisted of mixed clones of the original strains.

It might be argued that we here still have some form of symbiosis of
different genetic types, however,the evidence at least suggests strongly
that there is true exchange of charactere , which would indicate some
sort of sexual mechanism in bacteria.

L.M.Steinitz