Genomic bases of the clownfish adaptive radiation

Clownfishes (or anemonefishes) are considered as one of the rare marine examples of adaptive radiation. This small coral fishes form the Amphiprioninae subfamily, a  diverse group comprising about 30 species currently recognised as valid. Although very different in term of shape, color and habitats, all these species present unique characteristics such as a mutualistic interaction with tropical sea anemones, a complex social and mating system as well as an outstanding lifespan for this kind of organism. Whether this features are causes or a consequences of their amazing diversity, we are using both genetic, phenotypic and ecological data to understand how clownfishes diversified to this extent and over a relatively short period and what are the underlying genomic bases that could allow to explain their specificities.

Biogeography & systematics of the Indo-West Pacific Sergeant-majors (genus Abudefduf)

A. sexfasciatus (with black stripes on the tail) and A. vaigiensis (with yellowish spot on the back), two species that can occur in sympatry (Photo Joris Bertrand)

A. sexfasciatus (with black stripes on the tail) and A. vaigiensis (with yellowish spot on the back), two species that can occur in sympatry (Photo Joris Bertrand)

I have been involved in a research project whose aim was to study the systematics and the biogeography of several Indo-West Pacific fish species. Among them, the Sergeant-majors (genus Abudefduf) are part of one of the most diversified coral reef fishes family: the Pomacentridae. Several Abudefduf species are widely distributed and locally abundant so they can be considered as good biological models to investigate the causes of geographic variation within species and infer historical biogeography of species and regions where they live. My work contributed to show that the phenotype-based taxonomy of this fishes is not fully congruent with molecular systematics (Bertrand et al., 2017). Indeed, one of the Abudefduf species (Abudefduf vaigiensis) actually consists of distinct and quite divergent lineages whereas some populations of this species are also undifferentiated of another species (A. sexfasciatus) at mitochondrial genes, unravelling a complex evolutionary history involving inter-specific gene flow.