Evolution of viruses within a single host can be shaped by host life history and environment. Callinectes sapidus reovirus 1 (CsRV1) is a segmented dsRNA virus that i nfects C. sapidus across t wo hemispheres and a range of habitats. CsRV1 causes systemic infections and paralysis and mortality in the Atlantic blue crab, C. sapidus . Previous phylogenetic studies of a portion of the CsRV1 genome in US northern Atlantic coast and Brazil revealed geographically distinct viral genotypes.
To expand our understanding of the genetic diversity of CsRV1 across a broader temporal, geographic, and host connectivity range , we obtained 24 complete or near-complete CsRV1 genomes as well as segment 9 sequences 96 strains from the US Atlantic, Gulf coast, Caribbean Sea, and Brazil/Uruguay . The Maximum likelihood phylogenetic tree of CsRV1 concatenated genomes and segment 9 ORF suggested that CsRV1 genotypes are divided into major lineages of genotypes within the US Atlantic coast, Brazil and Uruguay Atlantic coast , Gulf of Mexico, and Caribbean Sea.
Full and partial genome analyses provide insight into the movement the virus across different scales and through time. For example, o ne CsRV1 genotype from Texas and several from Louisiana grouped with CsRV1 genotypes from the US Atlantic coast rather than genotypes from the Gulf of Mexico, which suggested long-distance transportation of CsRV 1, is consistent with human-mediated movement.
These results of this study can help us understand the origins and evolution of a marine virus and give clues to host population connectivity in the ocean. In addition, identified genetic variation s in each genomic segment of CsRV1 can also be employed to gain insights into the evolution dynamics of its viral genome over time.