Dormant in the oceans .. the discovery of more than 5 thousand RNA viruses | Sciences

Although many new RNA viruses have been identified, it is still difficult to determine which organisms they infect

RNA viruses are known for the diseases they cause in humans, from colds to Covid-19, and they infect plants and animals that are important to humans.

These viruses carry their genetic information in RNA instead of DNA, and RNA viruses develop at a much faster rate than DNA viruses, and although scientists have classified hundreds of thousands of DNA viruses in their natural ecosystems, RNA viruses have not been studied.

The discovery led to a doubling of the number of known RNA viruses from 5 to 10 (sites).

new search

This is what prompted a group of researchers to try to analyze the genetic material in the sea, which led to the identification of thousands of previously unknown RNA viruses, doubling the number of reefs or biological groups of viruses that may have existed, and team members published the results of their study. New in the journal Science.

The research team consists of a number of researchers in microbiology at Ohio State University, and the researchers explain in their article published on the website “The Conversation” that unlike humans and other organisms that consist of cells, viruses are not unique short pieces of “Di” did not. “. an A” can serve as a genetic barcode without which it will be difficult to distinguish between different types of viruses in nature.

To overcome this obstacle, the team decided to identify the gene that encodes a specific protein that allows the virus to replicate its genetic material, as it is the only protein that all RNA viruses have in common, and it plays a key role in how they reproduce Viruses have slight variations in the gene that encodes a protein that can help differentiate virus types.

There are more RNA viruses in the oceans than researchers previously thought.  (Guillermo Dominguez Huerta)
There are more RNA viruses in the oceans than researchers previously thought (websites)

The team therefore researched a worldwide database of plankton RNA sequences collected during the Tara Oceans expeditions, a 4-year ocean research expedition.

Plankton are any aquatic organisms that are too small to swim upstream, an essential part of seafood webs and a common host for RNA viruses. The team’s investigation eventually identified more than 44,000 genes encoding viral proteins.

new viruses

Later, the team used a form of artificial intelligence called machine learning to systematically organize these sequences and detect differences more objectively compared to performing this task by hand, and the team created a total of 5,504 new marine RNA viruses identified, which doubled the number R. .NA “is known from 5 to 10 corals.

By mapping these new series geographically, it revealed that two of the new reefs, Taraviricota, named after the Tara expedition, or Arctiviricota – Arctic Ocean viruses – were particularly abundant over vast sea areas, with regional preferences, whether in temperate or tropical waters.

This map shows the spread of RNA viruses across the ocean (Zayed et al.) Science Volume 376: 156 (2022).
This map shows the spread of RNA viruses across the sea (sites)

The team believes that Tarafiricotta may be the missing link in the evolution of the “RNA” viruses that researchers have been searching for for a long time, linking two different known branches of these viruses that differ in how they reproduce.

These new series will help scientists better understand not only the evolutionary history of RNA viruses, but also the evolution of early life on earth, as the Covid-19 pandemic has shown that RNA viruses can cause deadly diseases , but they also play an important role in systems Environment as it can infect a wide range of organisms, including microbes that affect environments and food webs on a chemical level.

Detecting RNA viruses in the world can help explain how they affect organisms that control many of the environmental processes that govern our planet. The study also provides improved tools that can help researchers catalog new viruses as genetic databases grow.

What’s next?

Although many new RNA viruses have been identified, it is still difficult to determine which organisms they infect, and researchers’ work is currently limited to sections of incomplete RNA virus genomes, in part due to their genetic complexity and technological limitations.

The team’s next step will be to learn what types of genes may be missing and how they have changed over time, and the discovery of these genes may help scientists better understand how these viruses function.

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