The Dogfish Scyliorhinus canicula: A Reference in Jawed Vertebrates

Abstract

INTRODUCTIONDue to their large size and long generation times, chondrichthyans have been largely ignored by geneticists. However, their key phylogenetic position makes them ideal subjects to study the molecular bases of the important morphological and physiological innovations that characterize jawed vertebrates. Such analyses are crucial to understanding the origin of the complex genetic mechanisms unraveled in osteichthyans. The small spotted dogfish Scyliorhinus canicula, a representative of the largest order of extant sharks, presents a number of advantages in this context. Due to its relatively small size among sharks, its abundance, and easy maintenance, the dogfish has been an important model in comparative anatomy and physiology for more than a century. Recently, revived interest has occurred 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 these 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 sequence, which may shortly become accessible, should establish 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.

Tangential migratory pathways of subpallial origin in the embryonic telencephalon of sharks: evolutionary implications

“…Nevertheless, there are no detailed studies about telencephalic tangential routes in basal vertebrates which prevent us from having a comprehensive view of forebrain evolution. The lesser spotted dogfish Scyliorhinus canicula represents a key species in evo-devo studies (Coolen et al 2009;Compagnucci et al 2013). It belongs to the class of Chondrichthyes (chondrichthyans or cartilaginous fishes), an ancient radiation of vertebrates considered the sister group of Teleostomi, i.e., the group of vertebrates with bony skeleton that gave rise to land vertebrates.…”

Strong population genetic structure and contrasting demographic histories for the small-spotted catshark (Scyliorhinus canicula) in the Mediterranean Sea

“…In general, it is a moderately important commercial species, which is primarily caught as bycatch in various demersal fisheries and retained for human consumption, oil extraction or fish bait (Compagno, 1984). It is also commonly displayed in public aquaria because of its relatively easy maintenance in captivity, while several thousand egg cases are produced annually to meet the needs of the international scientific community, which uses this species as a genomic model (Coolen et al, 2009).…”

A Developmental Approach to Forebrain Organization in Elasmobranchs: New Perspectives on the Regionalization of the Telencephalon

“…In the last few years, most if not all studies of development in elasmobranches have been carried out on a small shark, the Lesser Spotted Dogfish, Scyliorhinus canicula [for a review, see Coolen et al, 2009]. There are several reasons why this species is a good candidate for a 'model organism.'…”

“…In fact, the only modern and molecular information we have on the early development of the central nervous system in chondrichthyans comes from the studies of this group, whose members have analyzed the expression of developmental genes such as Pax6 [Derobert et al, 2002a], Emx [Derobert et al, 2002b], and Otx [Sauka-Spengler et al, 2001;Plouhinec et al, 2005] in embryos of the Lesser Spotted Dogfish from gastrulation to early organogenesis. Further support for the use of this species as a model organism has been provided by Coolen et al [2009].…”