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The Joshua Lederberg Papers

Letter from Joshua Lederberg to Jacques Monod pdf (112,646 Bytes) transcript of pdf
Letter from Joshua Lederberg to Jacques Monod
Number of Image Pages:
1 (112,646 Bytes)
1950-11-08 (November 8, 1950)
Lederberg, Joshua
Monod, Jacques
This item is in the public domain. It may be used without permission.
Medical Subject Headings (MeSH):
Genetics, Microbial
Lederberg Grouping: Correspondence B
Box Number: 7
Folder Number: 206
Unique Identifier:
Accession Number:
Document Type:
Letters (correspondence)
Physical Condition:
Series: Correspondence, 1935-2002
SubSeries: 1947-1953
Folder: Monod, Jacques
November 8, 1950.
Dear Jacques:
I trust that this letter will reach you before the October issue of Journal of Bacteriology. Through some oversight, my paper on o-nitrophenyl-galactosidase of K-12 omitted a reference to your note on lactase, and your subsequent longer paper in A.I.P. (which appeared while my ms. was in press). This was not, I think, serious, but I wanted to assure you that it was not intentional. The paper was written somewhat hastily, about a year after the experiments were completed, and sent off the day I left for a summer trip to Berkeley.
Not much done on lactase since, except that a mutant has come up which produces lactase constitutively (i.e., in full amounts on glucose-synthetic medium). Its relationships to Lac- lactase, or to the 7 or 8 Lac- loci are not clear, except that the "constitutive" mutation is epistatic (as far as lactase) to Lac3-. Esther has been cleaning up some of the loci, and has indications of even more than those previously listed, although the test for allelism is verified by very large scale crosses of Lacx- x Lacx- where the identical alleles are extracted from a single mutant source, via diploids, or of independent mutational occurrence.
Most recently, a large series of fresh isolates of E. coli have been screened for crossability to K-12. About a hundred have been tested; several cross with K-12 in good yield; a number of others with extremely low yields, but sufficiently to make it possible to transfer interesting genes to crossable stocks for detailed genetic analysis. Among the interfertile strains is Escherich's type culture, from the American Type Culture Collection. With one exception, which is intrafertile at the same low rate as X K-12, I have no information yet on the intra-fertility of the new strains.
May I enclose a request for Doctor Lwoff? We have heard from Ephrussi that UV induces phage-lysis of lysogenic coli. We have never noticed this with our routine work with K-12, and wonder about the details of the experiment. If we could be favored with a reprint on this effect, it would be appreciated, as we are anxious to reproduce the experiment. I am sorry we had no opportunity to compare notes during your visit, as Esther, especially, is working intensively on genetic aspects of lysogenicity in K-12.
Joshua Lederberg
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