Weinberg, Z. et al. Nat. Chem. Biol. 11, 606–610 (2015).

To understand evolution, it is important to have a comprehensive understanding of the possible catalytic roles RNA can play, roles that have been largely taken over by proteins. Only 11 classes of ribozymes have been validated to date, and only a few members of the six classes that show self-cleaving activity have known biological functions. To expand the known repertoire of ribozymes, Weinberg et al. devised a computational strategy that takes advantage of the fact that known self-cleaving ribozymes are located close to each other and to certain protein-coding genes. Looking for conserved secondary structures in these genomic locations led the researchers to identify new variants of the hammerhead and hepatitis delta virus ribozymes as well as entirely new classes of ribozymes, which they named twister sister, hatchet and pistol.