Reverse arrangement of rRNA subunits in the microsporidium Glugoides intestinalis

The rRNA gene cluster of microsporidia is typically arranged in the order small subunit-internal transcribed spacer-large subunit, which conforms with the general arrangement of these genes in nearly all organisms. We found a rearrangement of the cluster in the microsporidium Glugoides intestinalis, where the large subunit precedes the small subunit. Such a rearrangement has already been reported for several species in the microsporidian genus Nosema, and we provide evidence that the arrangement reported here is a second, independent event.