Molecular Studies of Cophylogeny: Microbes, Insects, and Mammals

Louisiana State University, Baton Rouge LA

Investigators

Abstract

DEB-0075381 Mark S. Hafner Dr. Mark S. Hafner, a zoologist at Louisiana State University, along with microbiologists Drs. Frederick Rainey and Naomi Ward-Rainey at the same institution have been awarded a grant to investigate the shared evolutionary history of three symbiotic organisms: small rodents called pocket gophers, the lice that live in the fur of the pocket gophers, and selected lineages of bacteria that live inside the lice. Previous research by Hafner his other colleagues has established that the pocket gophers and their lice have been living together for millions of years, resulting in nearly identical phylogenies (family trees) for the gophers and lice. The presence collaborative team now proposes to use molecular methods, including examination of DNA and RNA, to determine if the bacteria that live inside the lice also have shared a long history of association with their hosts. The major goal of this 2-year project is to characterize the bacterial community living inside the lice, and distinguish between lineages of bacteria that live more-or-less permanently inside the lice versus those that are mere transients passing through the louse's digestive tract. This research will require careful examination and comparison of both intra-louse and extra-louse (gopher-associated and free-living) bacterial communities; hence, an important byproduct of this research will be characterization of the microbial communities associated with the entire pocket gopher burrow system. The experimental approach will incorporate three lines of evidence: microscopic visualization of microbial communities inside the lice, culturing and DNA sequencing of bacterial lineages, and culture-independent molecular analyses of bacterial diversity. Ultimately, documentation of a long-term association between the bacteria and their hosts will allow for comparison of rates of genetic change in these two distantly related groups.