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The Joshua Lederberg Papers

Letter from Joshua Lederberg to Henry P. Treffers pdf (71,871 Bytes) transcript of pdf
Letter from Joshua Lederberg to Henry P. Treffers
Number of Image Pages:
1 (71,871 Bytes)
1951-08-08 (August 8, 1951)
Lederberg, Joshua
Treffers, Henry P.
This item is in the public domain. It may be used without permission.
Lederberg Grouping: Correspondence B
Box Number: 8
Folder Number: 91
Unique Identifier:
Accession Number:
Document Type:
Letters (correspondence)
Physical Condition:
Series: Correspondence, 1935-2002
SubSeries: 1947-1953
Folder: Treffers, H. Peter
August 8, 1951.
Dear Pete:
Some time ago, you mentioned in a letter that strain 58-278 showed an unusually high rate of mutation to Sr. I recently had occasion to use this information in experiments adding further proof to the evidence that resistance mutations occur independently of the selective environment. May I acknowledge the source of this information as a private communication from yourself in the paper Esther and I are writing?
The experiments use velvet to make replicas of the growth on plain agar to a series of streptomycin agar plates. Starting with an inoculum from plain broth, heavily spread on plain agar, and incubated a few hours, we find that the Sr mutants on replica plates are roughly superimposable, showing prior growth of clones. Furthermore, by using the congruent sites on plain agar for fresh inocula, we enrich for Sr, and in a few such indirect selections obtain Sr mutants in pure culture from populations never in contact with streptomycin. We finally succeeded in getting one clone from W-1; 58-278 was of course, much easier. Do you have any further information of the genetics of the high mutability?
With best regards,
Joshua Lederberg,
Associate Professor of Genetics
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