Scyliorhinus canicula Genome sequencing. Scyliorhinus canicula

As a chondrichthyan, the small spotted dogfish Scyliorhinus canicula, a representative of the largest order of extant sharks, occupies a key phylogenetic position to unravel the molecular bases of the important morphological and physiological innovations of jawed vertebrates. Due to its relatively small size, abundance, and easy maintenance, the dogfish has been an important model in comparative anatomy and physiology for more than a century. Recently, it has aroused a revived interest with the development of large-scale transcriptomic and genomic resources, together with the establishment of facilities allowing massive egg and embryo production. These new tools open the way to molecular analyses of the elaborate physiological and sensory systems used by sharks. They also make it possible to take advantage of unique characteristics of this species, such as organ zonation, in analyses of cell proliferation and differentiation. Finally, they offer important perspectives to evolutionary developmental biology that will provide a better understanding of the origin and diversifications of jawed vertebrates. The dogfish whole-genome project now underway establishes this species as an essential shark reference, complementary to other chondrichthyan models. These analyses are likely to reveal an organism of an underestimated complexity, far from the primitive prototypical gnathostome anticipated in gradistic views.