MINISTERE DE L'EDUCATION NATIONALE

 

CENTRE NATIONAL DE LA

RECHERCHE SCIENTIFIQUE

 

Jyne 27, 1957

LABORATOIRE DE GENETIQUE
PHYSIOLOGIQUE

GIF-SUR-YVETTE (SEINE-ET-OISE

Te. :

 

 

136 a GIF

Professor J. Lederberg
Genetics Building
University of Wisconsin
Madison 6, Wisconsin
U.S.A.

Dear Josh,

Thanks for your letter of June 14 and the various sugges-
tions it contains,

1) The dates of the Symposium I am organizing, which I gave you, are
tentative and I may have to modify them. Postponing the Symposium is
extremely difficult for several reasons. Shifting it to an earlier
date in March would be possible. I shall consider this after I get
the reply of the Navy.

Supposing we held it earlier in March and had Navy trans-
portation, could you come ?

2) I can now answer the question you asked in your letter of June 3
in conformity with our earlier published statements, B-26 retains—
the plasmids, i.e. gives normal ("grande") zygotes when crossed with
a vegetative petite.

We now have the recessive of B-26 in a marked chromosome
and can use the prototroph technique to study the kinetics of the loss
of the cytoplasmic factor : this is in fact what I have under investiga-
tion, as well as several other problems posed by the segregational
petites,

This, you will notice, signals my return to active work
and the petite problem which I, incidentally, find fascinating after a
year's vacation. Meanwhile, Hydra is going on slowly and rather desap-
pointingly.

With best regards to both of you,

Sincerely, ‘

Boris EPHRUSSI