ACADEMY OF MEDICAL SCIENCES OF USSR
—~—

INSTITUTE OF NEW ANTIBIOTICS

Bolshaia Pirogovskaia, I1
Moscow. USSR

 

 

gn ge

3. 1921—looo

September 6, 1974

Dear Professor Lederberg,

Many thanks for your letter of August 6. There are two
points which should be mentioned in connection with our more
recent work on induction of macro-mutants. Firstly,that this
induction is somewhat sporadic and difficult to reproduce.
Secondly that many induced mutants with altered DNA base
composition are not very viable, and perish in a few months
in subcultures. The latter observation perhaps indicates that
they are genuine, and not due to any contamination. I should
be happy if these results could be reproduced in different
laboratories.

At the moment I am much interested in a recent report
of your colleague Dr Stanley Cohen cohcerning possible trans-—
plantation of streptomycin genes into E. coli. Have these
results been already published in a scientific journal? I should
be grateful if you could send me any information on this point.

I am leaving tomorrow for Geneva, to participate ina
WHO meeting on screening for antitumor products.

Best regards.
Sincerely yours

\ AY Jour

Professor G.F, Gause,
Director