New Forms of Life

Late last year, it was reported that scientists had discovered new forms of life inside human bodies. They don’t match anything biology has classified.

A new class of RNA molecules was discovered inside bacteria that lives in the human body. They are circular genetic structures called obelisks. They differ from known viruses and bacteria. They appear to represent an unclassified category of RNA.

The discovery came from an analysis of genetic material obtained from microbial communities inside humans. Obelisks may be present across global populations. But their exact function is unclear.

These RNA entities are simple. They don’t encode proteins. They don’t form protective protein shells. They consist of short loops of RNA that replicate, although how remains a mystery.

More than 3,000 types of obelisks have been identified using computational tools designed to detect circular RNA structures in large genomic libraries. Researchers detected closed-loop RNA structures that lack protein-coding regions. As such, the molecules resemble viroids, which are also non-coding, circular RNAs. However, viroids infect plants, but obelisks are only found in human-associated bacteria.

Many of the obelisks are embedded in bacterial genomes, which suggests they may have adapted to specific bacterial hosts. No immediate health effects have been linked to obelisks, but their residence in bacteria that support digestion, immunity, and other function point to future research on the matter.

Obelisks don’t conform to definitions of viruses, plasmids, or other mobile genetic elements. They fall outside microbial categories.

The implications extend into evolutionary biology, particularly in the origins of RNA-based life. Some theories suggest early life may have relied solely on self-replicating RNA. Obelisks could offer insight into these early evolutionary stages.

Obelisks do exhibit genetic diversity. Different variants appear in specific regions of the body. This may reflect host-specific adaptations. It is unknown if they have any regulatory or ecological function in the microbiome.

There is scientific interest in non-coding and circular RNAs, which play roles in gene regulation and cellular function in plants and animals. Obelisks are different in that they seem to operate independently, with no participation in protein synthesis or cellular regulation.

The discovery shows that modern metagenomic-sequencing can detect molecular entities that don’t fit into established classifications.

Scientists expect further discoveries of novel RNA forms with unknown roles. It is not known if obelisks are ancient relics or modern molecular parasites. Research continues.

 

https://www.msn.com/en-us/health/medical/scientists-discover-new-forms-of-life-inside-human-bodies-that-don-t-match-anything-biology-has-classified/ar-AA1T7ARd?ocid=hpmsn&cvid=695189ccf8ea491b9920af677646366e&ei=56