The conservation of RFX TFs and ciliary IFT components in selected species. These species were selected to provide a wide sampling of the "tree of life". The phylogenetic relationship between each species was derived from the "Tree of Life Web Project" . Species indicated with "*" have ciliated cells based on published evidence. The 'RFX #' column shows the number of putative RFX TFs identified in this project or reported previously. The grey scale table shows the sequence conservation of individual ciliary components in each species. Darker shade represents higher sequence similarity and conservation. The numbers in each box indicate the percent identity revealed by the alignments between IFT genes and their corresponding human orthologs.