Submitted to: American Society for Microbiology Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/22/2005
Publication Date: 9/22/2005
Citation: McCuddin, Z.P., Dechaine, E., Cavanaugh, C.M. 2005. The role of host and habitat in the evolutionary history of chemoautotrophic symbionts [abstract]. North Central Branch-American Society for Microbiology. p. 27.
Technical Abstract: Prior phylogenetic analyses based on 16S ribosomal RNA (16S rRNA) have shown the chemoautotrophic symbionts of diverse marine invertebrates to be closely related gamma Proteobacteria, falling in 2-3 symbionts clades. Herein, additional 16S rRNA sequences for both chemoautotrophic symbionts and free-living gamma Proteobacteria bacteria have been included in the most comprehensive phylogenetic analyses of these organisms to date. Phylogenies were constructed using parsimony, maximum likelihood (ML), and Bayesian inference methods. The Bayesian and ML analyses revealed 3-4 symbiont-containing clades and showed several symbiont lineages are not monophyletic. Notably, all analyses showed several free-living bacteria grouping with the symbionts. The identification of free-living bacteria that are closely related to symbionts could represent a historical relationship between those symbiotic and free-living bacteria, with a habitat transition to an animal resulting in speciation, or represent an environmental reservoir for horizontally transmitted symbionts. This is the largest compilation of chemoautotrophic symbiont 16S rRNA sequences to date and serves as an invaluable tool for studies of cospeciation, inferences of symbiont transmission, and chemosynthetic habitat ecology.