Ohio State University microbiologists found more than 5,000 new RNA viruses in seawater samples collected around the world and increased the number of phyla they classified from five to 10. This new trove of data on RNA viruses expands the possibilities for ecological research and reshaps understanding of how these small but important submicroscopic particles evolve. The study was published in the journal Science.
The team collected seawater samples and sequenced them for viral RNA by searching for genes that encode RNA-dependent RNA polymerase (RdRp). The team then used supercomputers and machine learning algorithms to build phylogenetic trees for RNA viruses, finding a total of 5,504 new Marine RNA viruses and increasing the number of known RNA virus gates from five to 10.
The researchers grouped the newly discovered virus into five newly proposed gates. Mapping these new sequences geographically shows that two of the new gates are particularly abundant.
The researchers believe that one of the five newly discovered viral gates could be the missing link in the evolution of RNA viruses that researchers have long sought, linking two known branches of RNA viruses that differ in how they replicate. The discovery fills in some of the missing pieces in the evolutionary history of viruses.
Learning more about viral diversity and abundance in the world’s oceans will help explain the role of Marine microbes in ocean adaptation to climate change, the researchers said. The ocean absorbs half of the human-produced carbon dioxide in the atmosphere, and previous work by the team has shown that Marine viruses act as “knobs” on biological pumps, affecting how carbon is stored in the ocean.
In addition, these new viruses will help scientists better understand not only the evolutionary history of RNA viruses, but also the evolution of early life on Earth.
RNA viruses can cause deadly disease, as the COVID-19 pandemic has shown. But RNA viruses also play a vital role in ecosystems because they can infect a wide range of organisms, including animals, plants and microbes. Mapping where in the world these RNA viruses live helps illuminate how they affect the organisms that drive many ecological processes on Earth. The study could also help researchers classify new viruses as their genetic databases grow.