Meeting Abstract
P3.113 Tuesday, Jan. 6 Diversity in gene expression patterns during mammalian early tooth development ARMFIELD, Brooke A. *; THEWISSEN, J. G. M.; VINYARD, Christopher J.; NEOUCOM; Rootstown, OH.; NEOUCOM; Rootstown, OH.; NEOUCOM; Rootstown, OH. bgarner@neoucom.edu
Tooth morphology is one of the distinguishing features of mammalian species, however, little is known about how differences in form along a tooth row are genetically determined in mammals other than mice. To further explore the genetic patterning underlying the diversity of tooth morphologies seen in mammals we looked at early dental development of pigs and dolphins. These mammals are good models to address this question because they represent two variations in dental patterns. The domestic pig (Sus scrofa) dentition maintains several features representative of many mammals. They have two generations of bunodont teeth and a primitive-heterodont dental formula (3-1-4-3). In contrast the pan-tropical spotted dolphin (Stenella attenuata) has a highly derived homodont dentition, only one generation of teeth and an increased tooth number. It is known that in mice tooth type is determined early in development by signaling pathways establishing distinct boundaries for incisors and molars. We looked for expression patterns of these genes and proteins to establish associations between molecular events and dental classes across the three different dentitions. We used immunohistochemistry on dolphin embryos and in situ hybridization on pig embryos to determine the timing and location of proteins and genes (BMP4, FGF8, SHH) that influence early tooth type determination in mice. We found a range of expression patterns among these three mammal species. For example in dolphins, BMP4 expression was found to extend much more distally, perhaps contributing to the teeths incisor-like form. The variability in expression patterns suggest future developmental studies hold great promise in helping to explain the diversity in dental patterns across mammals. Supported by NSF.
