Since the beginning of the Covid-19 pandemic, RNA viruses, especially the Sars-Cov-2 coronavirus with its variants, have become known. RNA viruses are also causative agents of other diseases such as influenza, rabies, and HIV/AIDS.
A group led by Matthew Sullivan of The Ohio State University in Columbus, USA, is now showing how little is known about them in science. In the magazine “Science” The research team reported that they found the genomes of several thousand unknown ortho-RNA viruses, which include most RNA viruses, in water samples from all the world’s oceans. In addition to the five known strains, researchers have identified five new viral strains.
[Wenn Sie alle aktuellen Entwicklungen zur Coronavirus-Pandemie live auf Ihr Handy haben wollen, empfehlen wir Ihnen unsere App, die Sie hier für Apple- und Android-Geräte herunterladen können]
Terry Jones, who works with his group at the Institute of Virology at Charity University Hospital in Berlin, explains: Using computer methods to examine the DNA of new or long-extinct viruses.
“However, in their study, American colleagues carefully analyzed not just one bucket, but many seawater samples from all the world’s oceans,” says Charity’s computational virologist.
These water samples were collected over three and a half years and 125,000 km around the world by the French research vessel “Tara” between 2009 and 2013. Water samples were collected from up to 1,000 meters of water at 210 sites during the expedition.
Using newly developed bioinformatics strategies, Sullivan and his team found genetic information for enzymes called “RNA-dependent RNA polymerase” in these samples, which is shortened to RdRP after the English term “RNA-dependent RNA polymerase.”
In living organisms, these enzymes translate the information in the DNA genome into a closely related but clearly distinguishable RNA molecule. RNA serves as a template from which proteins can be produced. It is somewhat different with RNA viruses: the genome is made up of RNA. To multiply it, not only coronaviruses but most RNA viruses use RdRP.
Translation in the host cell
One of the previously unknown and discovered strains of the virus is the “Taraviricota” viruses. According to the analyzes of the American team, these pathogens appear to be outdated.
“This study is thus an important contribution to old and central questions about the evolution of RNA viruses,” explains Charité Jones. In their scientific article, American researchers suspect that the ancestors of these Taraviricota viruses could have evolved into the so-called retro elements at a time when life on Earth was just beginning to emerge.
Retro elements occur in the DNA genomes of animals and plants and under certain conditions can leave their ancestral location and move to another location in the genome.
During this process, retroelements are first translated into RNA like any other genetic information. A special enzyme called “reverse transcription,” which occurs in retroviruses such as HIV that causes AIDS, then converts this RNA back into DNA, which can be incorporated into a different location in the genome.
RNA viruses can influence the development of host plants, animals, and humans via retroviral elements. These jumping elements, for example, activated the amylase gene in the genome in the salivary glands of the human oral cavity, which is not active there in many other mammals.
With the help of amylase, people can better digest the starches found in plant foods like grains and potatoes, which are made up of long chains of sugar molecules. Gene activation by the hopper component gave humans an evolutionary survival advantage.
“Total coffee aficionado. Travel buff. Music ninja. Bacon nerd. Beeraholic.”