nov 7 1973

Yale Univer sity New Haven, Connecticut 06510

DEPARTMENT OF MICROBIOLOGY
310 Cedar Street

Telephone: (203) 436-1770
November 5, 1973

Dr. Joshua Lederberg

Department of Genetics

Stanford University School of Medicine
Stanford, California 94305

Dear Josh:

Thank you for the culture of W1485 which you sent to us in September. John Clark
checked it with the set of Ty phage that he has been using in his survey of suppressors
among our old strains and found that it shows no suppressor activity, to the great relief of
some of the Turopeans who have been using it as an ancestral stock. Apparently the stock
in the Paris lab did not carry the supE~ mutation that appeared in the Yanofsky stock,

_ which is now widespread. Curtiss has informed me that his W1485 stock shows suppressor
activity. He used it extensively as an ancestor.

Although it does not fit with the standard nomenclature, I have suggested that the
substrain bearing this suppressor be referred to in the future as W1485E. To call either
strain anything other than "W1485" at this point would be confusing, I think, and this was
the best solution I could come up with.

As you know, the cultures of Y10 and Y53 that you sent to us did not check out.
They would not grow on minimal plus By, thr, leu. We have received from A. Bernstein at
the Medical College of Wisconsin a lyophil of Y10 made in March 1955 by his wife, who
was then a graduate student of yours. This strain checked out all right and we are now
i 6 using it as our Y10. You are welcome to a lyophil of it -- if you want one.

I would like to get hold of a very old lyophil of wild-type K-12. AB264 of Adelberg
has phage mu at an arabinose locus. Groman's wild type is lac™ and 4ra~. We are currently
sending out Hayes' EMG2 as wild type, which seems to be all right, but I would feel more
comfortable if we could get one that we knew had been kept in lyophil since the very early
days.

If you can send us a very old lyophil of K=12 wild type, we would be most grateful.
‘ Best regards,
set 5 the bet ; | °
Ay Taree ‘ | _f> 4 “Bavaro
arbara J. Bachmann