Séminaire de l’Institut Jacques Monod – Mélanie Débiais-Thibaud 

Invitée par l’équipe Gazave, Mélanie Débiais-Thibaud (Institut des Sciences de l’Evolution de Montpellier, Université de Montpellier, CNRS, IRD, 34090 Montpellier, France) présentera un séminaire de l’Institut Jacques Monod sur le thème :

The vertebrate skeleton through the eye of a cartilaginous fish

Résumé :

Bone together with other mineralized tissues evolved early in the vertebrate lineage (more than 415 Myr ago), even before the evolution of jaws. Endochondral bone though has evolved as a general rule in the bony fish lineage only, to which most model organisms for developmental biology belong (tetrapods or teleost fishes). In the cartilaginous fish lineage however, bone is considered secondarily lost despite conspicuous mineralisation of the skeleton in the form of tessellated cartilage. Recently, an integrative set of data has informed the developmental dynamics, the cellular characteristics and the genetic actors of skeletal mineralisation in sharks and rays, in particular through the study of a non-model organism, the small spotted catshark Scyliorhinus canicula. These data have highlighted several aspects of cartilaginous fish-specific evolutionary events, including gene duplication, diverged developmental processes and probably cell type identity. Despite prolonged independent evolution in the bony fish and cartilaginous fish lineages, the comparative analysis of these data also helps identify an ancestral genetic toolkit, still to be discussed regarding other mineralised tissues in extant jawed vertebrates.