Site-specific AT-cluster insertions in the mitochondrial 15S rRNA gene of the yeast S. cerevisiae.

By comparing the mitochondrial 15S rRNA sequences of four wildtype yeast strains together with their respective secondary structures, with those of the 16S-like ribosomal RNA from other organisms we detected two optional and two invariant AT-clusters. The origin of these clusters is discussed with respect to their roles as possible mobile elements.