Air Nail

YALE UNIVERSITY
OSBORN BOTANICAL LABORATORY
NEW HAVEN, CONNECTICUT

June 9, 1950

Dr. Joshua Lederberg
Genetics Department
University of Wisconsin
Madison, "isconsin

Dear Josh:

Could you send me a culture of your strain #58-278? This strain
is the biotin-phenylalanine strain. Treffers,has been using this strain
investigating resistance to various drugs and the various mutants em which
he has tried this hae behaved in an anomalous fashion. It shows very
high mutation rates to Streptomycin resistance and Trefrers has found that
the strain I furnished him when plated out on a complete medium gave rise
to two types of colonies, large colonies and small colonies, The large
colonies are biotin-phenylalanineless and the small ones require neither
biotin nor phenylalanine but do require norvaline. We thought it might
be desirable to check a few independent cultures of this and I am writing
to both you and Ed in the hopes of getting your transfers of the stock of
this strain.

Best regards,

As ever,

Went

David h.. tonner
Associate Professor of Microbiology