Genetic Mosaicism Between The Bacteriophage ?80 And Bacteriophage ?

by Cramer, Todd James

Abstract (Summary)
Mosaicism may occur among the genomes of organisms as well as the viruses or bacteriophage that infect them. Some of these changes result from mutations, insertions, deletions, hybridization, generalized or specialized transduction, transformation, and conjugation. These changes to the genome often lead to strains and/or species different from the original. Comparing sequences of these new forms of the genome to their purported origins can help us further understand the evolutionary links between them and how they may have diverged. As bacteriophage lack ribosomal RNA, and no other universal characteristic exists that allows comparison of many different bacteriophage species to each other, it is clear that genomic and proteomic comparisons will play an invaluable role in the future of bacteriophage phylogenetics. The bacteriophage ?80 has an ~45,000 nucleotide linear dsDNA genome and infects several Gram-negative bacteria, including Escherichia coli, exploiting proteins in the bacteria’s outer membrane for host recognition and the bacterial cell itself for reproduction. The bacteriophage ?80 is a lambdoid bacteriophage, genetically and morphologically related to bacteriophage ?, which also infects E. coli. As ?80 and ? utilize different receptors for host recognition, it is likely that their respective genomes will differ in at least those aspects of the genomes that dictate host range specificity. Many other bacteriophage also infect E. coli, and it is possible that co-infection may occur. When this happens, recombination and reorganization between genomes may occur, creating a new version when viable progeny are released. By comparing the approximately forty percent (40%) of the known sequences of the genome of ?80 to already completed sequences of ? and other lambdoid and non-lambdoid bacteriophage, a clearer understanding of how these two bacteriophage are related has emerged and suggests that they are not as similar as previously assumed. The data presented here suggest that although ?80 is related to ? phylogenetically, its genome has diverged from the genome of ? considerably over a relatively short amount of time.
Bibliographical Information:


School:Bowling Green State University

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:genetics mosaicism bacteriophage ? ?80


Date of Publication:01/01/2008

© 2009 All Rights Reserved.