CDB Seminar - Katherine Criswell, Cambridge University

Host: Susan Evans

Talk abstract: The vertebral column is a key feature of the vertebrate skeleton, but there are stark differences in vertebral development between fishes and tetrapods, and thus the early evolutionary history of this fundamental structure is poorly understood. These developmental differences include the embryonic origins of different components of the vertebral skeleton, the segmental arrangement of somite cells in the eventual vertebrae, and the expression patterns of hox genes and their relationship to vertebral regions. My research focuses on studying axial skeletal development and morphology in a cartilaginous fish, the little skate (Leucoraja erinacea), to better understand the early evolution of vertebral development. Cartilaginous fishes occupy a key phylogenetic position as sister to bony vertebrates, and comparisons between cartilaginous and bony fishes can provide insight into evolutionary patterns of developmental processes and ancestral conditions in the last common ancestor of jawed vertebrates. In this talk I will present data from the little skate showing that many aspects of skate vertebral development align more with tetrapods than with teleosts. These results suggest that tetrapods and cartilaginous fishes share a common, and likely ancestral, mode of vertebral development, while in teleost fishes this process has diverged substantially.

Criswell KE, Roberts LE, Koo ET, Head JJ, and Gillis JA. 2021. hox gene expression predicts tetrapod-axial regionalization in the skate, Leucoraja erinacea. PNAS 118: Criswell KE and Gillis JA. 2020. Resegmentation is an ancestral feature of the gnathostome vertebral skeleton. eLife 2020;9:e51696.

Criswell KE, Coates MI, and Gillis JA. 2017. Embryonic origin of the gnathostome vertebral skeleton. Proceedings of the Royal Society B 284:20172121.

Criswell KE, Coates MI, and Gillis JA. 2017. Embryonic development of the axial column in the little skate, Leucoraja erinacea. Journal of Morphology 278:300-320.

Join Zoom Meeting: https://ucl.zoom.us/j/92560528628?pwd=YzRDT0tMcGc1bEdUeTllNW5aclFKUT09

Meeting ID: 925 6052 8628

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