A major discovery: what are “obelisks”, these mysterious viruses identified in the human body ?

L’analyse des bases de données de séquences a révélé de nouveaux génomes à ARN circulaire. Illustration Pete Linforth/Pixabay

A new type of viral entity that thrives in bacteria in the mouth and gut has been identified and could have an influence on our health. 

A discovery considered major in biology. A research team from Stanford University in San Francisco in the United States has identified previously unknown viral entities in the human mouth and intestines.

The work relating to this discovery was the subject of a pre-publication in the scientific journal Biorxiv on January 20, but it is already of interest to the scientific world. And for good reason, these little "viruses" could have consequences on our health. 

What are these kinds of viroids ?

This entity which is composed of RNA has been called "obelisk" by scientists. It uses bacteria that are present in the mouth or intestines of humans. as a host to be able to live and develop. 

Their name was chosen because they look like thin chopsticks, as Science explains. And according to researchers they are present in more than half of the samples taken from the mouth and in 7% from the intestine.

They are therefore very present and numerous in the human body, and could have an influence – harmful or beneficial this remains to be identified – on our body and our health.

And where these entities can be really interesting is that they are more complex than simple viroids. Without going into the scientific complexity, viroids are viral particles composed of a simple RNA and infect host cells and can thus cause pathologies. They are known to attack plants. 

But these viroids are more complete. "They comprise a class of diverse RNAs that have colonized and gone unnoticed in human and global microbiomes. They are unlike any other known entity", the researchers explain in their study. 

"We find that obelisks form their own distinct phylogenetic group, with no detectable sequence or structural similarity to known biological agents."

Already 29,959 obelisks identified

Researchers managed to distinguish 29,959 obelisks. It is especially surprising that these kinds of viruses have never been identified before. This study has caused a wave of interest in the scientific world and will lead to other research in the future.