The generalized secondary structure of the 18S rRNA sequence from Acanthamoeba, based on analogy with other eukaryotic 18S rRNA structure and the use of RNA folding programs to predict structure for regions specific to Acanthamoeba. The sequence shown is from a T4 isolate. Regions in red represent hypervariable regions of the structure that are unique to Acanthamoeba. Helix 29-1 represents a part of the molecule that is highly informative phylogentically, and that is included in a part of the molecule (the DF3 segment) that is often determined when only a portion of the 18S rRNA gene is sequenced.
