Retrozymes are a unique family of nonautonomous retrotransposons with hammerhead ribozymes that propagate in plants through circular RNAs

Catalytic RNAs, or ribozymes, are regarded as fossils of a prebiotic RNA world that have remained in the genomes of modern organisms. The simplest ribozymes are the small self-cleaving RNAs, like the hammerhead ribozyme, which have been historically considered biological oddities restricted to some RNA pathogens.