On the hunt for new viruses. And this time not in the bat caves of Asia or the forests of Latin America, but in the oceans and glaciers. In fact, it is precisely in the least explored environments on the planet that the greatest surprises are hidden. The microbes we know of are far fewer than exist, so it’s best to discover them before they can harm animals, plants, and of course humans.
- The new viruses in the oceans
- viruses on ice
The new viruses in the oceans
By analyzing thousands of plankton samples from all the world’s oceans, a team of researchers from Ohio State University (United States) has discovered 5,504 species new hitherto unknown ribonucleic acid (RNA) viruses. The team is part of the consortium Tara Oceans, a global project to study climate change in the oceans. The results of the study were published by Science.
In general, the most studied viruses are those that contain deoxyribonucleic acid (DNA), but many of the new ones are made of RNA. These “are known for the diseases they cause in humans, ranging from the common cold to COVID-19, and also infect plants and animals,” the authors write in a statement. “These germs evolve much faster than those of DNA,” they say. usual, finding could help virologists to understand the evolutionary history of RNA viruses.
But there is more: also provides insight into how early life forms evolved on earth. In fact, these microbes play a key role in ecosystems precisely because they interact with the organisms that make up them and direct biological processes on our planet. “We want to systematically study RNA viruses on a large scale and explore an environment that no one else has explored in depth,” the study authors said.
Five new taxonomic groups
This is how the scientists analyzed: 35,000 water samples taken from 121 locations in the world’s oceans. They then extracted genetic sequences from plankton, the tiny aquatic organisms at the base of the food chain that are also a major reservoir for viruses.
To distinguish the RNA sequences from each other, the researchers looked for the presence of an ancient gene called RdRp. It is only present in ribonucleic acid microbes and is used to make a protein essential for replication. They found 44,000 sequences with this gene. To determine which species they belonged to, they turned to artificial intelligence that could organize them and identify the new viruses. The machine learning it was also instrumental in ordering the new species.
In reality, scientists found such diversity that they numbered the known phyla. had to double Until now. Phyla is a category of taxonomy that is between kingdom and class. The new classification adds five more, up to 10, and rewrites the evolutionary relationships between one group and another. New phyla includes: Taraviricota (with most newly discovered species), pomiviricota, paraxenoviricota, wamoviricota Y arctiviricota.
Two of those new phyla were found to be particularly abundant in specific oceanic regions: arctiviricota in the Arctic Ocean and Taraviricota in the waters of temperate and tropical climates. Especially the latter is assumed the missing link in the evolution of RNA viruses. Something that experts have been looking for for a long time and that connects two well-known evolutionary branches.
viruses on ice
The deep ocean isn’t the only place scientists look for new viruses. The Ohio State University already had a year ago published the discovery of 28 groups of frozen unknown organisms on a 15,000-year-old ice sheet in Tibet.
At about 6,700 meters above sea level is one of the oldest glaciers on Earth. It’s called Guliya, about 200 square kilometers of ice crust that started to form before the end of the last ice age. This makes it a formidable record of the last 130,000 years of planetary history. For example, we can find out what happened to the atmosphere half a million years ago.
The scientists took two samples at a depth of 50 meters, that is, an ice of 15,000 years. Inside dozens of unknown bacteria found and managed to identify 33 groups of viruses, 28 of which were new. The researcher Zhi-Ping Zhong, responsible for this study, stated: “Glaciers are shrinking rapidly and this could at least lead to the loss of evidence of the Earth’s climatic regimes. But in the worst-case scenario, the melting of the ice could also release very dangerous pathogens.” Therefore, finding and studying new microbes can help prevent future disease outbreaks.
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Photos |Cristian Palmer/Unsplash, Jairo Gallegos/Unsplash, CDC/Unsplash