April 23, 1969

Dr. Renkicht Takata

Research Institute for Nuclear
Medicine and Biology

Hiroshima University
Kasumi-cho, Hfroshima, Japan

Dear Dr. Takata,

The history of strain W3637 is indicated on the attached
diagram. W 3135 and W3637, according to our strain notebook,
were produced by Dr. Alan Richter on the dates indicated. W3135
is mentioned briefly by Dr. Richter in his paper in Genetical
Research, Vol.2, on page 336. W3637 has not,as far as I know,
been mentioned in print.

W1655 is quoted in my paper in Genetics, Vol.38, page 55,1953.

Since the strains are so old I cannot recommend that you draw
any important conclusions by a comparisén of isolates at different
stages in the pedegre. Instead you should initiate some new crossing
experiments with W3637, in particular re-introducing the F+ factor
into it and cross this strain to another F- streptomycin sensitive
whose ribosomal proteine you have studied. If the alteration of
ribosomal protein is associated with streptomycin resistante by your
tests it would indicate that the same gene conferred resistance and
the protein change.

If, however, it is impowtant for you to have these old cultures
I will try to get them out again for you. But I can give you no
guarantee of their present agreement with the indicated genotype.

Sincerely yours,

Joshua Lederberg
Professor of Genetics

Enclosure

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