Daniel Paluh, a Ph.D. candidate in David Blackburn’s lab, has been awarded a 2021 National Science Foundation Postdoctoral Research Fellowship in Biology (PRFB). The Fellowship will fund Dan’s postdoctoral research on the developmental and molecular mechanisms of convergent tooth loss in frogs in the Fraser lab, Department of Biology, University of Florida. This project is in collaboration with the Department of Organismic and Evolutionary Biology, Harvard University.
- For more information see: https://nsf.gov/awardsearch/showAward?AWD_ID=2109344&HistoricalAwards=false
- To read Dan’s new paper on this work, published this week in the Journal ‘Evolution’, see the following link: https://onlinelibrary.wiley.com/doi/10.1111/evo.14379
Re-evaluating the morphological evidence for the re-evolution of lost mandibular teeth in frogs
Abstract: Dollo’s law of irreversibility states that once a complex structure is lost, it cannot be regained in the same form. Several putative exceptions to Dollo’s law have been identified using phylogenetic comparative methods, but the anatomy and development of these traits are often poorly understood. Gastrotheca guentheri is renowned as the only frog with teeth on the lower jaw. Mandibular teeth were lost in the ancestor of frogs more than 200 million years ago and subsequently regained in G. guentheri. Little is known about the teeth in this species despite being a frequent example of trait “re-evolution,” leaving open the possibility that it may have mandibular pseudoteeth. We assessed the dental anatomy of G. guentheri using micro-computed tomography and histology and confirmed the longstanding assumption that true mandibular teeth are present. Remarkably, the mandibular teeth of G. guentheri are nearly identical in gross morphology and development to upper jaw teeth in closely related species. The developmental genetics of tooth formation are unknown in this possibly extinct species. Our results suggest that an ancestral odontogenic pathway has been conserved but suppressed in the lower jaw since the origin of frogs, providing a possible mechanism underlying the re-evolution of lost mandibular teeth.