April 18, 1952

Dr. L. M. Black
Brookygn Botanic Garden
1000 Washingtcn Ave.,
Brooklyn 25, N.Y.

Dear Dr. Elack:

Thank you very much for letting me study the enclosed manuscript in
advance of publication. As I told you at Cinncinnati, I am preparing a
review of the genetic implications of symbloses. I was already acquainted
with Fukushi's 1940 paper (why doesn't Bawden cite it?), and with Maraneo-
rosch's work, but was very pleased to see your conclusive account.

There are a couple of points that are,mentioned, but not emphasized, in
your ig. which cre particularly important as genetic phenomena. With clover
club-leaf virus, may I infer that crosses of infected males x noninfected
females give sntirely ncninfected progeny (as Fulasshi showed with rice-stunt) ?
Also, you refer to a heat effect. Can infected females be disinfected with
heat, with respect to their progeny as well as tne treated generation? Have
you noticed any skips, i.e. a non-infectious female mothering an infectious
progeny. (I was act clear about table 2 in this regard).

fo turn to wound~tumor virus. The transovarian transmission is implied
on p.l6é. Has this been systematically studied? Has the same problem been
considered with aster yellows?

I would appreciate 4t very much if you could let me know whether I may
quote your answers as "private communication", or better if you think they
are adequately treated in a publication. I shall look forward to the appearance
of this review in print, and will be indebted to you for reprints of your forth~
coming papsrs on ths subject.

In our work with Salmonella transduction, it is beginning to look very much
as if the "FA" particles are actually phage particles. Evidently, under certain
special circumstances, "lysogenic" viruses can also transfer fragments of tts
genetic material of the host cells on which they are grown. Ordinarily, the
bacteriolytis effect of virus infection precludes the possibility of detection
of such transductions. Ifvyou wanted to look at it in a certain way, thas is
the converse of the transovarian transmission of a virus.

Yours sincerely,

Joshua Lederberg