Fully-Sequenced Genomes of the Representative Organisms Included in This Study.
| Organism | Domain | Genome size (Mbp) | Number of predicted ORFs | Description | Reference |
| Pyrococcus abyssi | Archaea | 1.77 | 1765 | hyperthermophile; chemoorganotroph | R. Heilig (unpub.) |
| Methanococcus jannaschii | Archaea | 1.66 | 1767 | hyperthermophile; chemolithotroph; anaerobe | Bult et al. 1996 |
| Escherichia coliK12 | Bacteria | 4.6 | 4290 | facultative aerobe | Blattner et al. 1997 |
| Thermotoga maritima | Bacteria | 1.86 | 1849 | hyperthermophile; chemoorganotroph; anaerobe | Nelson et al. 1999 |
| Mycobacterium tuberculosis | Bacteria | 4.4 | 3294 | causative agent of tuberculosis | Cole et al. 1998 |
| Helicobacter pylori | Bacteria | 1.7 | 1565 | survives under acidic conditions; microaerophile; human pathogen | Tomb et al. 1997 |
| Synechocystis sp. strain PCC6803 | Bacteria | 3.6 | 3167 | unicellular cyanobacterium | Kaneko et al. 1996 |
| Saccharomyces cerevisiae | Eukarya | 12 | 6294 | unicellular fungi | Goffeau et al. 1996 |
| Caenorhabditis elegans | Eukarya | 97 | 22898 | multicellular eukaryote | The C. elegansSequencing Consortium 1998 |
| Drosophila melanogaster | Eukarya | 180 | 14118 | multicellular eukaryote | Adams et al. 2000 |