More than 5,000 new types of viruses have been identified in the world’s oceans, according to a new study.
Study researchers analyzed tens of thousands of water samples from around the world, looking for RNA viruses, or viruses that use RNA as hereditary material. The new coronavirus, for example, is a type of RNA virus. These viruses are studied in comparison to the DNA viruses that use DNA As genetic material, the authors said.
The diversity of the newly discovered viruses was so great that the researchers suggested doubling the number of taxonomic groups needed to classify RNA viruses, from the current five to 10 phyla. (Era is a broad classification in biology that falls under “kingdom.”)
“There is a lot of new variety here – and complete diversity [new] A phylum, Taraviricota, is found throughout the oceans, indicating that it is ecologically important,” study lead author Matthew Sullivan, professor of microbiology at Ohio State University, said. He said in a statement (Opens in a new tab).
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According to Sullivan, studies of RNA viruses have typically focused on those that cause disease. (Some well-known RNA viruses include influenza, Ebola, and the coronavirus that causes COVID-19.) But this is only a “small slice” of RNA viruses on Earth, Sullivan said.
“We wanted to study it systematically at a very large scale and explore an environment that no one had looked at in depth,” Sullivan said in the statement.
For the study published Thursday (7 April) in the journal Science (Opens in a new tab)In the study, researchers analyzed 35,000 water samples taken from 121 sites in all five of the world’s oceans. The researchers are part of the Tara Ocean Consortium, a global project to study the impact of Climate change on the ocean.
The researchers said they examined genetic sequences extracted from small aquatic organisms known as plankton, which are common hosts for RNA viruses. They settled on sequences belonging to RNA viruses by searching for an ancient gene called RdRp, which is found in all RNA viruses but is absent from other viruses and cells. They identified more than 44,000 sequences with this gene.
But the RdRp gene is billions of years old, and it has evolved many times. Because the gene’s evolution goes way back, it has been difficult for researchers to determine the evolutionary relationship between the sequences. So the researchers used machine learning to help organize them.
Overall, they identified about 5,500 new species of RNA viruses that fell into the five existing classes, as well as the five newly proposed classes, which the researchers named Taraviricota, Pomiviricota, Paraxenoviricota, Wamoviricota, and Arctiviricota.
Virus species in the Taraviricota phylum were particularly abundant in temperate and tropical waters, while viruses in the Arctiviricota phylum are abundant in the Arctic Ocean, the researchers write in Conversation. (Opens in a new tab)
Understanding how the RdRp gene varies over time can lead to a better understanding of how early life develops LandThe authors said.
“RdRp is presumed to be one of the oldest genes – it was present before DNA was needed,” study co-first author Ahmed Zayed, a research scientist in Ohio State microbiology, said in the statement. So we trace not only the origin of viruses, but also the origins of life.
Originally published on Live Science.