Secondary structure, high variability and conserved motifs for domain III of 12S rRNA in the Arthropleona (Hexapoda; Collembola)

The robustness of different hypothetical structural models for ribosomal RNAs can be established by comparing sequences from widely different taxonomic groups. Secondary structure models of the two mitochondrial ribosomal subunits have been proposed for a large number of pterygote insects, but little information is available for the more ancient entognath hexapods. We have investigated the most frequently sequenced of the four domains of the mitochondrial small subunit rRNA in twenty-two collembolan species in the taxon Arthropleona. We provide secondary structure models of this third domain for representative species, and a consensus based on all species studied. This consensus is in partial agreement with previous models. High levels of variation, in terms of length and of primary sequence, are present in the peripheral portions of the domain. Some of the structural elements differ more among genera of springtails than among insect orders. Conversely, a limited number of structural differences compared with other taxa have been detected in the core regions.