Table 1. A comparison of the presence (+), absence (−) or number of detectable ORC subunit and Cdc6 proteins encoded by the genomes of a range of eukaryotic species, which are grouped into taxa and into five supergroups; ‘+’ in parenthesis indicates that a single protein is found that is related to both Orc1 and Cdc6.
| Supergroup | Taxon | Organism | Orc1 | Orc2 | Orc3 | Orc4 | Orc5 | Orc6 | Cdc6 |
| Excavataa | Diplomonadida | G. lamblia | (+) | − | − | + | − | − | (+) |
| Euglenozoa | T. brucei | (+) | − | − | + | − | − | (+) | |
| T. cruzi | (+) | − | − | + | − | − | (+) | ||
| L. major | (+) | − | − | + | − | − | (+) | ||
| Heterolobosea | N. gruberi | (+) | + | − | + | − | + | (+) | |
| Parabasala | T.vaginalis | + | + | − | + | − | − | + | |
| Chromalveolata | Stramenopile | T. pseudonana | + | + | − | − | − | − | +(2) |
| Apicomplexa | T. annulata | + | + | − | + | − | − | + | |
| P. falciparum | + | + | − | + | + | − | + | ||
| C. parvum | + | + | − | + | + | − | + | ||
| Ciliophora | T. thermophila | + | + | − | + | + | − | + | |
| Plantae | Viridiplantae | A. thaliana | + | + | + | + | + | + | + |
| Amoebozoa | Entamoebidae | E. histolytica | + | − | − | − | − | − | + |
| Mycetozoa | D. discoideum | + | + | + | + | + | + | + | |
| Opisthokonta | Microsporidia | E. cuniculi | + | + | − | + | − | − | + |
| Fungi | S. pombe | + | + | + | + | + | + | + | |
| S. cerevisiae | + | + | + | + | + | + | + | ||
| Metazoa | D. melanogaster | + | + | + | + | + | + | + | |
| H. sapiens | + | + | + | + | + | + | + |
a
the supergroup Excavata is often split into two supergroups, one containing Euglenozoan, Heterolobosean and Jackobid (not shown) organisms, and the other containing Parabasalid, Diplomonad and Oxymonad (not shown) organisms.