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UNIVERSITY of PENNSYLVANIA

PHILADELPHIA 4

The School of Medicine

DrraRTMENT OF MICROBIOLOGY

May 13, 1957.

Dr. and Mrs. Joshua Lederberg
Department of Genetics
University of Wisdensia
Madison 6, Wiseonsin

Dear Joshua and Esther: .

I have been reading your reprint on
Cellular Mechanioms in Differentiation and Growth with the
greatest interest. May I have another copy for graduate
student use in the preparation for prelins?

In comnection with your discussion
of the closer resemblance of K-12 progeny to the F- perent,
is it mot now possible to be a little more explieit? 1
think there is pretty good cytological evidence for the
existence of more than one set of linked genes (chromosome)
per mucleus, at least ina B. mogatorium and BE, 09}4. Te it

mot possible to suppose that o one chromosome passes from
the Hfr to the F” conjugent?

‘9s f9gnH

o I was indeed happy to learn from con-
versetion with Dr. Erdman that your father and mother are
now able to make out at home, although I an sorry to under-
stend that your father cannct resume his professional duties.

Cordially yours,

SM: jlh Stuart Mudd
7 4

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