Eukaryotic ribosomes that lack a 5.8S RNA

Abstract
The 5.8S ribosomal RNA is believed to be a universal eukaryotic characteristic1. It has no (size) counterpart among the prokaryotes, although its sequence is homologous with the first 150 or so nucleotides of the prokaryotic large subunit (23S) ribosomal RNA. We report here an exception to this rule. The microsporidian Vairimorpha necatrix is a eukaryote that has no 5.8S rRNA. As in the prokaryotes, it has a single large subunit rRNA, whose 5′ region corresponds to the 5.8S rRNA.