Verschlimmbessern

Verschlimmbessern is making something worse by a well-meaning but misguided attempt to make it better. It is a common source of error in genome annotation.

Example 1: In some bacteria, the 23S ribosomal RNA precursor has an intervening sequence (IVS) that is excised during ribosome biogenesis. 23S rRNA is part of the large subunit, or 50S subunit, whereas 16S rRNA is part of the small subunit, or 30S subunit. The symbol S refers to the Svedberg unit, and describes a property of sedimentation during ultracentrifugation. Pfam model PF05635 describes a protein often encoded in this IVS, making it a "bacterial 23S rRNA protein". However, this name is similar in form to the series of names for proteins of the ribosomal small subunit, from "ribosomal protein S1" up to "ribosomal protein S21", where S designates small subunit. In public databases, this protein family reflects successive rounds of Verschlimmbessern, with the name morphing to "23S rRNA protein," to "23S ribosomal protein," to "S23 ribosomal protein," and in one case onwards to "30S ribosomal protein S23."