5,500 hitherto unknown species of RNA viruses, many of which have required the creation of new groups for classification: they have been discovered in the waters of the oceans, thanks to the analysis of 44 thousand genetic samples of organisms floating in the sea.
The result, published in the journal Science, is due to the Tara Oceans Consortium, led by the American Ohio State University and which is conducting a global study, still ongoing, carried out on board the schooner Tara.
The discovery has important implications for understanding the impact of climate change on the oceans, but also for the evolution of life on Earth.
"RNA viruses are clearly important in our world, but we usually investigate only a small fraction of them, the few hundred viruses that pose a threat to humans, plants and animals," comments Matthew Sullivan, one of the leading authors of the According to the researchers, learning more about the diversity and abundance of viruses in the world's oceans will help explain their role in the adaptation of the oceans to climate change, also because the sea absorbs half of the carbon dioxide (CO2) emitted by the man in the atmosphere and the viruses identified hold the key to understanding how this mechanism occurs.
Since viruses have the ability to transfer their genes to other organisms they infect, the authors of the study took tens of thousands of genetic RNA sequences from the ocean, looking for a precise signature: the RdRp gene. which has evolved for billions of years only in RNA viruses and whose existence dates back to the birth of life on Earth.
"RdRp is supposed to be one of the oldest genes: it existed before DNA evolved," observes Ahmed Zayed co-author with Sullivan. "So we're not only tracing the origins of viruses - he adds - but we're also tracing the origins of life".
