Description
Viruses and bacteriophages have understudied but consequential associations with metazoan hosts. Sharks in the family Carcharhinidae have unique epidermal properties which help to cultivate a unique microbiome, but the virome of shark skin has never been studied. In this study I used next-generation sequencing techniques and a novel bioinformatics pipeline to characterize and compare the epidermal virome taxonomy of three Carcharhinid shark species from the southwestern Pacific, Carcharhinus obscurus, Carcharhinus galapagensis, and Galeocerdo cuvier. The analyses yielded the largest marine vertebrate virome dataset ever compiled and generated several complete novel phage genomes. Epidermal viromes from all three shark species shared many common taxa and were dominated by bacteriophages with a small proportion of eukaryotic viruses. The relative proportions of the shared taxa varied somewhat among shark species, and not all taxa were present on all sharks which caused C. galapagensis viromes to differ significantly from C. obscurus viromes despite the close relation between those sharks. Several identical phage genomes were shared across all three shark species, but some of these contained genes associated with temperate replication that were missing in their counterparts from other shark species, indicating the potential for dual replication strategies within a single strain.
