The University of Chicago

CHICAGO 37, ILLINOIS

 

Institute of Radiobiology and Biopbysics

f
J: be tlerbh Bp u
Y., > 1 55 Rest
fe r et 9 f be fer efnt ob Le ftir Chicage 7, 1 Street

i oy
od . A ‘ June 1, 1948
Dr. 8. E. Luria

Departuent of Bacteriolegy

Indiana University
Bleeningten, Indiana

Deer Luria:

1a view of the conversation which ve hed vhen you lest visited
Chioage, you night be interested in the felleving remit; during the last
ek Heviek and I played around with the K strain of soli used by Leterbers
and Tatan, Ne used a strain 58/161, which requires bietin ani methionine,
ana wetes im the fallowing I shall designate as *f,* ant a strain ¥, whieh re-
quires threonine, leucine, ani thiania, Beth strains were sent te us from Ned-
isen by Lederberg.

We prepared the phage resistant mtaats £/iy £/65 W/ly W/6y — C/A
aut Wi deatgnate here mtante viieh are resistant beth to phage 1 and te phage
5.

First ve crossed W/6 and C/) end pieked 57 ealenics, out ef vaich
7 were resistant to all three phages 1, 5, and 6; and ealy one ves sensitive
to all three phages 1, 5, and 6, The rest of the oslenios vere resistent either
te phage 1 or phage 6, (Sensitivity and resistance to phages 1 and 5 alvays
went together in this experinent, )

Subsequently ve crossed W/l ami £/6 and out of 60 eclenies picked
caly 1 vas resistant te all three phages 1, 5, end 65 and 30 vere sensitive
to all three phages 1, 5, and 6, The rest of the celenies vere resistant
8, g. Luria waa June 1, 1948

te either phage 1 or phage 6.(Gensitivity and resistance to phages
1 and 5 always went together in this experiment).
If this is net recombinatien of character, I shall eat ay hat,

With kindest regards,
Sincerely,

Leo Ssilard

LS:an
cot M, Delbruck