This project seeks to characterize, through DNA sequence analysis, the evolutionary relationships among members of the bacterial genus Photobacterium. These bacteria are very common in the world's oceans, colonizing marine animals as benign skin or intestinal inhabitants, in some cases causing disease, in others forming beneficial symbiotic associations with the animals based on the bacterium's luminescence. Despite the worldwide distribution and environmental importance of this group of bacteria, what distinguishes one kind of Photobacterium from another, how many different kinds there are, and what criteria should be used to define a Photobacterium species are unresolved problems, a situation that is common to all bacterial groups and that impedes progress in many areas of biomedicine, industry, and basic science. To resolve these problems, genetically different kinds of Photobacterium, identified by DNA fingerprinting, will be isolated from marine habitats. From these bacteria, several genes, chosen for their ability to reveal evolutionary relationships for members of the group, will be sequenced and the sequences analyzed to reconstruct their evolutionary history and establish DNA sequence criteria for defining a Photobacterium species.
This project will have a wide scientific impact on understanding the nature and extent of the differences in DNA sequence that determine whether different bacteria belong to different species. The sequence information from this project will be made available through public databases. The project provides training to student participants in the areas of systematics, microbial biology and symbiosis, and these scientific themes and specific results from the project will be incorporated into undergraduate courses taught at the University of Michigan in microbial biology. More broadly, a publicly accessible web site designed for the general public, the K-12 classroom environment, and the general science community will make available information from this project on Photobacterium, emphasizing the natural history, ecological distributions, and environmental activities of its different members.
