Bridging the Phylogenetic Gap : The Small-Spotted Catshark as a Key Model Organism in Evolutionary Developmental Biology
The evolution and diversification of vertebrates is largely associated with changes in their developmental programs. In order to reconstruct the evolution of developmental programs, species from different phylogenetic lineages are typically compared. Despite the expansion of available species in the recent years, current research remains biased towards bony vertebrates (Osteichthyes), which includes the classical model organisms: mouse, chicken, clawed frogs, and zebrafish. As a consequence, a key vertebrate lineage remains comparatively understudied: Chondrichthyes (cartilaginous fishes). In this thesis, I re-introduce the small-spotted catshark (Scyliorhinus canicula) as a powerful chondrichthyan model organism in evolutionary developmental biology (evo-devo) with the aim to bridge the gap between the emerging field of lamprey research and the vast information gathered from osteichthyan model organisms. I generate a high-resolution atlas of the developing small-spotted catshark combining combining synchrotron radiation micro-computed tomography (SRµCT) with gene expression mapping. Subsequently, I characterize the developmental dynamics of CNCCs as well as facial morphogenesis. Collectively, I identify heterochronic and heterotopic changes in developmental programs, as well as providing novel insights into chondrichthyan development. Overall, this work expands the evolutionary developmental framework by integrating morphological and molecular data from an underrepresented vertebrate lineage. It demonstrates the feasibility of applying cutting-edge methodologies to non-model organisms, and establishes a foundation for future comparative studies. The resources generated here will be made publicly available, offering valuable tools for the scientific community and aiding in the broader inclusion of Chondrichthyes into evo-devo research.
Rights
Use and reproduction:
Please note that individual components of the publication may be subject to other licensing or copyright conditions.