Obelisks: They Are Living In You

Not only can we report on the discovery of a new life form, it’s living inside of us! Wait, just you and me? We can debate if we’re human (chuckle), although, sometimes I’d like to take a break from being human. No kidding! Since we can’t, back to the episode - a new life form! Hidden among the microbiome of our mouths and guts are thousands of virus-like entities scientists have named obelisks.   

These strange RNA are also in bacteria, and there’s already a debate over whether they’re alive. Scientists discovered the obelisks while analyzing huge collections of RNA sequences extracted from human stool and saliva samples.  RNA, short for ribonucleic acid, is a molecule that can carry genetic information. Scientists discovered the obelisks when they saw more than thirty thousand distinct circular RNAs in the database that don’t look like any other RNAs.  

While viruses, even those with RNA genomes all have a protein coat, obelisks lack one.  They resemble plant pathogens called viroids which are also made of RNA and lack a protein coat.  But that’s where the similarity ends. Viroid RNAs do not encode any proteins while obelisks encode unique proteins called oblins.  It is not known what these proteins do in bacteria or human cells, if anything.   

We have so many questions: what are they? Are obelisks evolutionary relics? Are they precursors to viruses? How do they impact our health? We’ll need more studies but for now, this is a fascinating work in progress!