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Part One: Some Theoretical Problems Arising in the Genetics of Bacteriophage. Part Two: A Critical Test of a Current Theory of Genetic Recombination in Bacteriophage


Steinberg, Charles Myron (1961) Part One: Some Theoretical Problems Arising in the Genetics of Bacteriophage. Part Two: A Critical Test of a Current Theory of Genetic Recombination in Bacteriophage. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/YYKR-0Q08.


ABSTRACT OF PART ONE: Calculations are presented giving the distribution of clone-sizes of mutants arising in an "equilibrium pool" of vegetative phage. It is assumed that replication and maturation are random-in-time processes. The equilibrium pool model is an idealization of current notions about a major portion of the phage life cycle. The calculations are compatible with experimental measurements of the mutant clone-size distribution. It is also shown that the model can account for the observed variance in total burst size. A generalized theory of the kinetics of genetic recombination in phage is presented. Essential assumptions of the theory are that recombination occurs as a result of discrete interactions or matings, and that the particles which participate in a mating are randomly chosen from the entire population of the vegetative pool. No restrictions are placed upon the number of particles that participate in the mating or upon the mechanism by which recombination occurs as a result of the mating. Experimental observations leading to the theory are discussed as well as the prospects for experimental determinations of the participation number and the mechanism of recombination. ABSTRACT OF PART TWO: Results are reported concerning the segregation pattern of loosely linked outside markers within a selected class of particles which are recombinant for closely linked internal markers: (a) The outside markers maintain qualitatively normal linkage relations with the internal markers and with each other. This is true whether one or two exchanges are required to produce the selected recombinant class. (b) The region of HNI extends into the intervals adjacent to those in which the exchanges are selected but does not extend into a non-adjacent interval. (c) Multiple exchanges within the selected class occur with little, if any, additional interference. (d) A significant fraction of the selected recombinant class is heterozygous for at least the adjacent outside markers. In summary, aside from the "complications" of negative interference and heterozygosis, the segregation pattern of outside markers is "normal." In view of current notions concerning the mechanism of recombination in phage, the "complications" are to be expected, while the "normal" result leads to a paradox. According to observations of other workers, recombinants for very closely linked markers arise as segregation products of phage heterozygotes, and furthermore, such heterozygotes are recombinant for outside markers. On the other hand, result (a) above means that recombinants for closely linked markers are not necessarily recombinant for outside markers. Some possible resolutions of this paradox are discussed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Virology and Physics)
Degree Grantor:California Institute of Technology
Major Option:Biology
Minor Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Delbruck, Max
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1961
Record Number:CaltechETD:etd-08082006-084127
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3044
Deposited By: Imported from ETD-db
Deposited On:09 Aug 2006
Last Modified:21 Nov 2023 18:58

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PDF (Steinberg_cm_1961.pdf) - Final Version
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