February 1, 1957

Dear Dave:
Thanké for the prompt reply.

Your comments were well enough taken; they have all been complied with
and the ms. will be sent in Monday after being retyped. I hope that "F is
remarkable for ite high contagiousness" will be agreeable. We had no intemion
of raising the issue you pointed out, at least not here, though I do distinguish
F, which oan spread through a population (i.e. increase faster than the cells)
from ang other marke, which does segregate/ on crossing.

Your commente:

1)— phrane deleted. &) as supra. 3) Explicit enough, but addendum to
footnote 4 that plates are among suitable methods when convenient. 4) Mis-
reference. Stooker Zinder ani L was intended. We will either revise, and shift
10,.. accordingly, delete, or make a more awkward reference to 3. 5) have delegted
statement, and leave just a bare reference to Hirota without comment. [But

Alan Richter and Ann Cook both tried to repeat, without success. Ditto for
Eisenstark's claim of 750 X inorease in fertility with wersene trea tment. ]

We have dons mauusmi controle on plate reinfection, using 3-way mixture
of F+, Hfr, F~. The (marked) progeny of Hfr x i'~ are almost always F- on same
plates as F+ x F- come out alwaya F+. This is my principal objection to the
necesaity of F+ -» Hfr to account for all fertility of F+. Alan has som
unstable ©. <9 ui, where the F+ croas-pogeny are less frequent, and

come out F+, the tr cross—progeny come out F-.

I didn't want to encourage unwarranted talk at a delicate point in the
discussions, but I oan tell you something now of possible plans, that you my
hear mis-rusored. .

We went out to California over Christmas to discuss possibilities with
Stanfords vice Ed Tatup in Biology there. Thenm we took a week's vacatdon at
Berkeley, where my brother liyes. While there, the Genetice Departant learned
of the purpose of our travelling, and promptly taustmba tendered an offer
which has recently become fairly firm. We are very sorely tempted, and have a
hard job trying to decide which if either. Meamhile, a Medical Genetics

nprogram (department?) idea is catohing fire here, which has some extremely
attractive possibilities. We are moh in a quandary, and this is one reason
I've been so slow getting other work out this month. But as one of our friends
has said, none of the alternatives is exactly distasteful, except having to make
a choics.

Why is UCIA so improbable?
Please confirm whether the reprint arrangement suggested will be ok.

Best wishes,
P.S. Had you preserved ahy serotypic recombinants,

8: a wgl x ig lc mags Rutiex® Frite Orskov has Ch
standard serum, they could eas hua ‘berg
be run throgugh. , ty doshugil Adar