We also analyzed three bacterial species Escherichia coli K12 MG1655 , the cyanobacterium Synechococcus elongatus PCC 7942 , and the alphaproteobacterium Rickettsiales bacterium Ac37b  and three Archaea species Ignicoccus hospitalis kin4/i, Nanoarchaeum
equitans , and Lokiarchaeum sp.
El arbol fue construido con el metodo estadistico "neighbour-joining", con un bootstrap de 1000 repeticiones y usando como "outgroup" a Nanoarchaeum
The rooted tree, which was used to simulate clock-like behavior, revealed the early divergence of Nanoarchaeum equitans and then Archaea .
This rooting is based on unique and ancestral genomic traits of Nanoarchaeum equitans, split genes separately codifying for the 5' and 3' halves of tRNA and the absence of operons, which are considered molecular fossils .
Ki et al., "Unique substrate spectrum and PCR application of Nanoarchaeum
equitans family B DNA polymerase," Applied and Environmental Microbiology, vol.
Because Ignicoccus is Latin for "fireball," Stetter named its microbial partner Nanoarchaeum
equitans to indicate a dwarfarchaeum riding a fiery sphere.
Professor Karl Stetter, who has spent more than 20 years looking for the bug, has named it Nanoarchaeum
For instance, Nanoarchaeum
equitans lacks most of the genes for metabolic and biosynthesis process [12, 26].