Cold Spring Harbor
November 1, 1956
Dr. Joshua Lederberg
Department of Genetics
University of Wisconsin
Madison, Wisconsin

Dear Josh,

"Eg Sorty I've been th ediipse for “So Tong. “Thanks *for:Jear: comments cn the
sequential transfer’ manuscript. As You have seen, they éand 860 late to bes >
considered, bat fortunately soins’ of ‘your’ coPtedct ions’ had: alPeady been. cadgnt
T'think that most of the réemainiiiz disagreement 1s" polemics':+ 1) nope: that: the ‘paper
33 not misunderstood. For example, I'went’ fiito some détatd on the'Het’ story with
the intention of making clear that there was evidence for post-zygotic elimination,
and that in fact it might alsd oomir; in’ addition to prezygotic elimination, in
non-Het cepsses. Also I intended that the expression "breakage" subsume such a
thing as a point of stress. Thus I used the word "discontinuity" in the summary.
Having agreed that these points of "breakage" cr stress were variable, the questicn
of whether they are breakage or stress points was considered. The end conclusion
gdeexxefxemurxe is ofcourse that they are breakage points (since this is simpler -cr
so my argument goes). As to the role of spreading in separating pairs, I don't see
that this is called for by the data. If spreading does do this, however, my argument
would be that thermal agitation alone can also probably do the same thing, I'm not
clear myself on why there is a discrepancy between the kinetics of pairing as det'd
by JW and ourselves. My attempts at communication with Jacob have not been toe
successful. I snet him a summary of results about a year ago; he replied noncemittally
but scooped us a few months later on the reverse sequence of transfer.

As you may knew, I've been working on the linkage of tryptophan mutations in
coli. Nine B/r mutants have been analyzed; all are clustered closely and seem to
be in the proper functional order. There is some messiness however, which I have
been struggling with and hope to clear up soon. B/1 tyrtophaneless are apparently
deletions for the entire tryptophane synthesizing region. Yanofsky and Lennox have
obtained almest identiacl results, but we are in amicable communication. One of my
difficulties is in obtaining high titer lysates of the mutayt Pl which I use for
intra-B/r transductions.

With regard to the F* to F- conversion, I have a result to report which is
either an amazing coincidence or a significant finding. The F- strain which I
obtained when I first came to CSH (by swarming) from 58-141) has been foun? to
have an additional requirement for proline. I have been stewing for a chance to
look at this phenom. further but haven't had a charce. Maybe it would be wise
to check all of the independent F- derived by swarming which you have, to see if
this or any other requirement has been added. I can think of several wild but
interesting possibilities. (The F- strain I mention is called CS2; it is truly
F- and the additional prol- is appar. linked te TL, prob. to richt of Lac.)

I am definitely in the market for something next year. I'm on an NSF grant which
extends till Jan. 58, but this is an awkward termination point. I'd be grateful to
hear about anything interesting. I wrote to Georgia for more information; I also
had a letter from Florida State about a somewhat similar position.

I was disillusioned about the reprint-previding-capacity of Detrick, and
consec. have almost run out of "Binary Mut" reprints. ‘Were any of those you
requested to be sent out? If so I have enclosed a list of people to whom J have
given reprints im to prevent duplication.

(over)
Some time age, J-asked yeu to check with Bill Stone about those croess=rx.
experiments,. Beth ke ard Wilmer Milier had indicated that they were intersted
in. doing something on th: subject. ke to round than cut for public. I wag
interested in. getting. straighterd out who. wanted te do what. Did you ever speak
-te Bill] or sheuld I write him at. long last? oo

.. Best regards te Esther,
° wh
. cea an ole

aces