Nearly complete rRNA genes from 371 Animalia: updated structure-based alignment and phylogenetic analysis

This study presents a manually constructed alignment of nearly complete rRNA genes from most animal clades (371 taxa from ∼33 of the ∼36 metazoan phyla), expanded from the 197 sequences in a previous study. This thorough, taxon-rich alignment, available at http://www.wsu.edu/≃jmallatt/research/rRNAalignment.html and in the Dryad Repository (doi: http://dx.doi.org/10.5061/dryad.1v62kr3q), is based rigidly on the secondary structure of the SSU and LSU rRNA molecules, and is annotated in detail, including labeling of the erroneous sequences (contaminants). The alignment can be used for future studies of the molecular evolution of rRNA. Here, we use it to explore if the larger number of sequences produces an improved phylogenetic tree of animal relationships. Disappointingly, the resolution did not improve, neither when the standard maximum-likelihood method was used, nor with more sophisticated methods that partitioned the rRNA into paired and unpaired sites (stem, loop, bulge, junction), ...