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The Joshua Lederberg Papers

Title:
Reverse-Mutation and Adaptation in Leucineless Neurospora Annotation pdf (972,525 Bytes) ocr (29,097 Bytes)
Reverse-Mutation and Adaptation in Leucineless Neurospora
Description:
Lederberg's work under the tutelage of his mentor, Francis J. Ryan at Columbia University.
Number of Image Pages:
11 (972,525 Bytes)
Date:
1946-06 (June 1946)
Creator:
Ryan, Francis J.
Lederberg, Joshua
Source:
Periodical: Ryan, Francis J., and Joshua Lederberg. "Reverse-Mutation and Adaptation in Leucineless Neurospora." Proceedings of the National Academy of Sciences of the United States of America 32, 6 (June 1946): 163-173. Article. 11 Images.
Lederberg UI: P1
Publisher:
National Academy of Sciences (U.S.)
Rights:
This item is in the public domain. It may be used without permission.
Subject:
Medical Subject Headings (MeSH):
Mutation
Genes
Exhibit Category:
The Development of Bacterial Genetics
Relation:
Lederberg Grouping: Published Scientific Article
Metadata Record Letter from Joshua Lederberg to David Perkins (March 3, 1983) pdf (41,362 Bytes)
/ps/access/BBGMRY.pdf
Metadata Record Letter from David Perkins to Joshua Lederberg (March 8, 1983) pdf (44,682 Bytes) ocr (789 Bytes)
/ps/access/BBGMRZ.pdf
Box Number: 79
Folder Number: 1
Unique Identifier:
BBABEL
Accession Number:
3
Document Type:
Articles
Language:
English
Format:
application/pdf
image/tif
Physical Condition:
Good
Series: Writings
SubSeries: Published Scientific Articles
Folder: P1: "Reverse-Mutation and Adaptation in Leucineless Neurospora" (1946)
Metadata Last Modified Date:
2009-07-15
Linked Data:
RDF/XML     JSON     JSON-LD     N3/Turtle     N-Triples

Annotation by Joshua Lederberg:
KW: heterokaryons; reverse mutation leucineless Neurospora;

My work under Ryan's tutelage.  He had originally observed "adaptation""
in growth tubes with leu- Neurospora.  I must have had many arguments
with him about possible mechanisms, including the most obvious: reverse
mutation.  This had not previously been documented with auxotrophs!
And barring selective procedures, it was barely known at all in
Drosophila etc.  Today of course it is a ubiquitous nuisance!

The main finding was that backcrosses of revertants to wild type
gave no auxotrophic progeny.  This of course might be defeated by a
moderately closely linked suppressor.

More perplexing was the population dynamics of the leu+/leu- heterokaryon:
Paradoxically, leu- nuclei would prevail given any selective
platform at all.  This is not understood at all.  Something analgous
may occur with pantothenate +/-  cf. Rowland H. Davis @ UC/I.
 Am J Botany  47:648-654 1960; it may be tied in with broader issues of
heterokaryon incompatibility, though these are usually connected with
the mating type locoi.


This is discussed further by Ryan (1946) - Cold Spr Harb Symp

Not every leu+ strain is inhibited by leu-., and by TH Pittenger
& TG Brawner  Genetics 46:1645-1663  1961

Ryan was concerned that the effects of leucine might be seen as
somehow lamarckian.

jl 7/25/98








Elementary question : is this selection at level of nuclei or of
competing multinucleate hyphal tips?


jl 7/16/98