P3.74 Friday, Jan. 6 The Dynamic Network of Scute Formation MOUSTAKAS, Jacqueline E*; CEBRA-THOMAS, Judith; HÄKKINEN, Teemu; JERNVALL, Jukka; GILBERT, Scott F; Institute of Biotechnology, University of Helsinki, Finland; Department of Biology, Millersville University, Millersville, PA; Institute of Biotechnology, University of Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Finland; Department of Biology, Swarthmore College, Swarthmore, PA email@example.com
The turtle shell, a classic case of morphological novelty, is composed of endochondral axial skeletal elements overlain by plates of dermal bone and keratinous scutes. Previously, we have shown that, as in the development of several other ectodermal organs, the keratinous scutes form by an epithelial-mesenchymal interaction that is regulated by Shh-Bmp2 signaling. Here we examined the growth dynamics of the turtle shell in an ontogenetic series using genetic markers for scute placodes as landmarks. We used the expression of these genes in the placodes to construct a distance map in a time-series of embryonic development in the red-eared slider turtle Trachemys scripta to visualize the growth of the shell. We then constructed distance maps of developing scute placodes in a population of embryos at the same stage of development to measure their coefficient of variation and thereby examine variation, stability, and the development of anomalies in turtle scutes.