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Title: Preliminary studies on the genetics of bacteriophages capable of generalized transduction.
Authors: Hedges, R. W.
Award date: 1969
Presented at: University of Leicester
Abstract: Theoretical arguments are presented to indicate that bacterio- phages capable of generalized transduction are also capable of forming composite genetic structures containing DNA sequences from the bacteriophage genome and also DNA from other genetic elements. These modified bacteriophage genomes - comparable with ? dg genomes should be capable of effecting transduction. Various techniques for isolating such modified bacteriophage genomes are discussed all of which require that transduction be effected under conditions in which the transduced fragment cannot be integrated into the genome of the recipient. Transduction of strains which have suffered large deletions, of strains that have lost (by mutation) the ability to undergo recombination, of fragments of an episome into a strain not carrying an homologous episome and of chromosomal genes between different bacterial genera. Attempts to isolate modified prophages by all four techniques are described. The only experiments that lead to well defined and regularly repeated were experiments in which bacteriophage ? 15 (or a mutant of this bacteriophage deficient in ability to effect antigenic conversion) was grown on a strain of Salmonella anatum carrying an F' factor integrated into which was a segment of DNA derived from the chromosome of Escherichia coli and selection was made among the recipients for those which had acquired genetic markers from the E. coli DNA. In the early experiments the lactose operon of an Flac episome was the genetic marker transduced. Among the transductants were strains carrying defective ? 15 prophages which had suffered loss of various genetic markers. Some of these transductants were immune to superinfection: others were not. Some of the trans-ductants were effective lysogens producing HFT lysates. Since the Salmonellae have no lactose operon, transduction of these genes is a special case. Studies on transduction of the Escherichia arabinose operon gave encouraging preliminary results. Some experiments concerning genetic instability are also described.
Type: Thesis
Level: Doctoral
Qualification: Ph.D.
Rights: Copyright © the author. All rights reserved.
Appears in Collections:Theses, Dept. of Genetics
Leicester Theses

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