The taxonomic tree covers all host organisms and can be easily browsed by clicking on and .
Every taxon name links to the search form with a corresponding query.

Taxonomic tree:

 cellular organisms (579 species, 12046 genes, 606 RNA sequences)
 Archaea (54 species, 1088 genes, 76 RNA sequences)
 Crenarchaeota (11 species, 272 genes, 12 RNA sequences)
 Euryarchaeota (41 species, 778 genes, 59 RNA sequences)
 Nanoarchaeota (2 species, 38 genes, 5 RNA sequences)
 Bacteria (238 species, 6368 genes, 139 RNA sequences)
 Actinobacteria (22 species, 700 genes, 3 RNA sequences)
 Aquificae (1 species, 42 genes, 0 RNA sequences)
 Bacteroidetes/Chlorobi group (5 species, 149 genes, 0 RNA sequences)
 Chlamydiae/Verrucomicrobia group (7 species, 262 genes, 0 RNA sequences)
 Cyanobacteria (9 species, 192 genes, 5 RNA sequences)
 Deinococcus-Thermus (3 species, 98 genes, 6 RNA sequences)
 Firmicutes (55 species, 1528 genes, 25 RNA sequences)
 Fusobacteria (1 species, 33 genes, 0 RNA sequences)
 Planctomycetes (1 species, 72 genes, 0 RNA sequences)
 Proteobacteria (108 species, 2602 genes, 61 RNA sequences)
 Spirochaetes (7 species, 266 genes, 0 RNA sequences)
 Tenericutes (17 species, 373 genes, 39 RNA sequences)
 Thermotogae (2 species, 51 genes, 0 RNA sequences)
 Eukaryota (287 species, 4590 genes, 391 RNA sequences)
 Acanthamoebidae (1 species, 10 genes, 0 RNA sequences)
 Alveolata (10 species, 110 genes, 11 RNA sequences)
 Cryptophyta (2 species, 6 genes, 0 RNA sequences)
 Euglenozoa (10 species, 80 genes, 10 RNA sequences)
 Fungi/Metazoa group (195 species, 3574 genes, 263 RNA sequences)
 Glaucocystophyceae (1 species, 8 genes, 0 RNA sequences)
 Mycetozoa (3 species, 24 genes, 1 RNA sequences)
 Rhodophyta (3 species, 29 genes, 0 RNA sequences)
 stramenopiles (4 species, 47 genes, 0 RNA sequences)
 Viridiplantae (58 species, 702 genes, 106 RNA sequences)
 Viruses (8 species, 53 genes, 17 RNA sequences)
 dsDNA viruses, no RNA stage (6 species, 53 genes, 13 RNA sequences)
 Caudovirales (4 species, 34 genes, 13 RNA sequences)
 Herpesvirales (1 species, 8 genes, 0 RNA sequences)
 Phycodnaviridae (1 species, 11 genes, 0 RNA sequences)
 Retro-transcribing viruses (2 species, 0 genes, 4 RNA sequences)
 Retroviridae (2 species, 0 genes, 4 RNA sequences)

*sequences of unknown strains are linked to the corresponding organism