The development and evolution of chondrichthyan gill arches and their appendages

Theme: World-Class Underpinning Bioscience

This project will investigate the patterning of chondrichthyan gill arches and their appendages in the little skate (Leucoraja erinacea), which is the established developmental model system in the Gillis Lab. Appendages have long been central to the study of pattern formation and organogenesis. For example, studying tetrapod limb development has yielded fundamental insights into axis establishment, signalling centres, and coordinated cell proliferation, movement and differentiation in the vertebrate embryo. Cartilaginous fishes are the only extant vertebrates that possess branchial rays, appendages that extend laterally from their gill arches, and which have been hypothesised to be serially homologous to paired fins and limbs. This project will use gill arches as a system to study skeletal pattern formation as well as to test this hypothesis of serial homology, by examining the role of developmental signalling pathways such as retinoic acid in patterning branchial rays, by employing experimental embryological manipulations, by dissection of signalling pathway function in vivo, as well as fate mapping techniques and gene expression analysis (in situ and RNAseq). This project will deepen our understanding of basic mechanisms of vertebrate appendage patterning, and may also shed light on the evolutionary origin of paired fins and limbs.

This project will involve bioinformatics relating to the analysis of RNAseq transcriptomic data regarding differences in gene expression along the dorsoventral axis of developing gill arches, statistical analysis thereof, imaging of in situ hybridisation experiments, and statistical analysis of experimental data such as fate-mapping.