What happened
A Science feature reports laboratory evidence that an RNA intron can move from a predatory bacterium into its prey without a viral carrier. The study came from Germany’s Max Planck Institute for Marine Microbiology and is presented as direct visual evidence of horizontal gene transfer across species.
The researchers worked with a mixed microbial culture derived from wastewater from a sewage plant. The culture contained a methane-producing archaeon, Methanothrix soehngenii, and a predatory ultramicrobacterium, Velamenicoccus archaeovorus.
How the transfer was tracked
The team identified the organisms in the mixed culture using RNA sequences, especially ribosomal RNA. In Velamenicoccus archaeovorus, a 23S rRNA precursor is produced and edited by removing an intron that can circularize and carry information for movement.
To trace the intron, the researchers used an RNA tracking probe developed at the same institute. The probe targeted the intron sequence and carried a fluorescent label. Live cells and dead cells emitted different fluorescent signals, helping the team distinguish the intron signal in the culture.