title: Diversification of two lineages of symbiotic Photobacterium.
abstract: Understanding of processes driving bacterial speciation requires examination of closely related, recently diversified lineages. To gain an insight into diversification of bacteria, we conducted comparative genomic analysis of two lineages of bioluminescent symbionts, Photobacterium leiognathi and 'P. mandapamensis'. The two lineages are evolutionary and ecologically closely related. Based on the methods used in bacterial taxonomy for classification of new species (DNA-DNA hybridization and ANI), genetic relatedness of the two lineages is at a cut-off point for species delineation. In this study, we obtained the whole genome sequence of a representative P. leiognathi strain lrivu.4.1, and compared it to the whole genome sequence of 'P. mandapamensis' svers.1.1. Results of the comparative genomic analysis suggest that P. leiognathi has a more plastic genome and acquired genes horizontally more frequently than 'P. mandapamensis'. We predict that different rates of recombination and gene acquisition contributed to diversification of the two lineages. Analysis of lineage-specific sequences in 25 strains of P. leiognathi and 'P. mandapamensis' found no evidence that bioluminescent symbioses with specific host animals have played a role in diversification of the two lineages.
authors.affiliation: Interdisciplinary Research Organization, University of Miyazaki, Miyazaki, Japan.
authors.forename: Henryk
authors.initials: H
authors.lastname: Urbanczyk
authors.affiliation: Interdisciplinary Research Organization, University of Miyazaki, Miyazaki, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Urbanczyk
authors.affiliation: Division of Bioenvironmental Science, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan ; Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Division of Bioenvironmental Science, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan ; Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Ogura
mesh_terms: D000818:Animals; D004269:DNA, Bacterial / Q000235:genetics*; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial / Q000502:physiology*; D009693:Nucleic Acid Hybridization; D010776:Photobacterium / Q000145:classification / Q000235:genetics; D010802:Phylogeny; D013559:Symbiosis / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial