Redundant and non-functional guide RNA genes in Trypanosoma brucei are a consequence of multiple genes per minicircle

The mitochondrial mRNA of the parasitic protozoa Trypanosoma brucei is extensively edited by the insertion, and occasional deletion, of uridine residues. The editing is mediated by over 200 guide RNAs (gRNAs) that are encoded in circular DNA molecules called minicircles. There are some 250 different types of minicircle, called classes, with each encoding several gRNAs. Sequencing of gRNAs and minicircles has revealed a surprising amount of both …