Fibropapillomatosis (FP) is a panzootic plaguing all species of sea turtles with green turtles having the highest percentage of affliction. Although fibropapilloma-associated turtle herpes virus (FPTHV) has been identified as the causative agent of FP, the primary vector triggering this chronic tumor-forming disease is still unknown. Parasitic marine leeches (Ozobranchus spp.) could be a potential mechanical vector behind the emergence of this panzootic, although it is uncertain if it is species specific. Ozobranchus spp. are very small and difficult to distinguish anatomically, and until now, there have been few attempts to document them. DNA barcoding using mitochondrial cytochrome c oxidase I (COI) gene as a molecular marker is a tool for identifying organisms and is especially useful for sea turtle leeches. Two species of leeches present along the Florida Atlantic coast are Ozobranchus branchiatus and Ozobranchus margoi. The known hosts reported for O. margoi include a variety of sea turtle species, such as green (Chelonia mydas) and loggerhead (Caretta caretta) sea turtles, but the only reported host for O. branchiatus has been C. mydas.
DNA barcoding was applied to samples of both species of leeches obtained from sea turtles captured at Indian River Lagoon and the St. Lucie Nuclear Power Plant in Florida (refer to Figure 1). DNA sequences were translated to protein sequences for alignment purposes. O. margoi is already present in the National Center for Biotechnology Information (NCBI) GenBank (AF003268), but leeches morphologically identified as O. branchiatus did not have a match in the genetic database. As a result, we used our DNA sequencing to add the O. branchiatus leech as a new species to GenBank (GU985465 and GU985466). There was a small but significant variance between the nucleic and amino acid sequence of the O. branchiatus leeches unexpectedly identified on a loggerhead and those found on green sea turtles, respectively from St. Lucie and Indian River Lagoon. The fact the O. branchiatus leech has changed specificity serves as an indication as to why the panzootic affecting mainly C. mydas initially has now appeared to a lesser degree in other turtle species.
This poster was created and presented by Triet M. Truong at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 16, 2010, the Chemistry Department annual Posters in the Hall student research event on June 4, 2010, the 41st Central Regional Meeting of the American Chemical Society on June 17, 2010, and at Carnegie Mellon University Bridging Research Communities event on October 16, 2010.
Truong, T. M.,
McGowin, A. E.,
& Corbett, A. M.
(2010). Identification of Sea Turtle Leeches Using DNA Barcoding. .
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