Fig. 2. Biogeography of viruses putatively infecting bacterioplankton under the Ross Ice Shelf.

A viral gene sharing network analysis was performed with a total of 6752 partial and full-length genomes, and more than 600,000 relationships (edges) are shown. Viruses from Global Ocean Viromes 2.0 database (GOV2), environmental and isolated viruses from Genbank (NCBI), archaeal and bacterial viral references, viruses from single-virus genomic surveys (vSAG 37-F6), viruses from Southern Ocean and Malaspina expedition were included in the analyses. Edges between nodes indicate a statistically significant weighted pairwise similarity between the protein profiles of each node with similarity scores ≥1 (see “Method” section for more details). Viral clusters are determined by applying the Markov Cluster Algorithm (MCL) to the edges according to Roux et al.²⁰ and Martinez-Hernandez et al.⁴⁶. Gene search similarity results shown in pie diagrams was carried out with open reading frames predicted from RIS viruses and the rest of viruses from the above mentioned virus databases. Abbreviations: International Committee of Viral Taxonomy (ICTV).