October 12, 1948

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Dr. Me. R. Zelle

Department of Racteriology
Cornell University

Ithaca, New York

Dear Zelle:

I was pleased to hear from you; sorry I didn't realize you were
arriving at Cornell so late.

As to the scope of the program, I think that is entirely up to
you. I would be very pleased to be the junior author of any publi-
cation which resulted from collsborative work on the single-cell
isolates. I am carrying through our studies without single-cell,
and hope to have these ready for publication before too much longer.

I would prefer an arrangement whereby I could get back the single
cell isolates for detailed charagterizations. I think we probably
are better equipped to do that both from the point of view of facilities
and close experience,

As it stands now, the picture is rather complex, The heterozygotes
seem to be deficient for some loci on one of the chromosomes, and I have
evidence that apart from segregation, there’ are occasional changes in
the structure of the heterozygote, essentially of the character of fur-
ther losses of chromosome parts, These deletions would undoubtedly be-
have as lethsls when hemizygous, and could account for the non random
segregations, The capacity to produce heterozygous progeny in crosses
is transmitted; I am studying its inheritance,

"An evenings work", merely the isolation of a few single hetero-
zygote cella, would be very helpful-indeed, if only to prove that a
cell can be heterozygotic, and I would be srateful for it, but I think
the problem merits a more extended study.

Just on the long chance you might be near New York City at the
time, I might mention that I expect to be in New Haven the week of
November 2, A perscnkl discussion would be more profitable than a
dozen letter,
page 2 -- October 12, 1948 M. Re Zelle

Inasmuch as we are developing new and better stocks all the time,
I'm going to wait until you give me the word that you ere ready to begin
operations before sending them. I can send you-all the medio that would
be needed,

With best wishes to you in your new pcst,

Yours, *

+

Joshua Lederberg
Assistant Professor of Genetics