Table 5.
Summary of data used to support actinobacterial ancestry of archaea.
| Trait | Supports actinobacterial ancestry of Neomura | Supports actinobacterial Ancestry of Eukaryotes | Exclusive to Actinobacteria among Bacteria |
|---|---|---|---|
| 20s proteasome | Yes | Yes | In a few other bacterial genomes |
| CCA added post-transcriptionally | No | No | Also in Firmicutes |
| Sterols | No | Yes | In a few other bacterial genomes (HGT), but only ones that could be vertical are actinobacterial |
| Chitin | No | No | Not in Actinobacteria |
| Serine/threonine signaling system | No | Yes | In Firmicutes too |
| Tyrosine Kinase | No | Yes | In many bacteria |
| H1 linker histone | No | Yes | In many bacteria |
| Calmodulin | No | Yes | In many bacteria |
| Phosphatidylinositol | No | Yes | Apparently unique to Actinobacteria, but related enzymes in other groups |
| Serine proteases | No | Yes | In many bacteria |
| Primary structure of α-amylase | No | No | In a few other bacterial genomes |
| Fatty Acid synthetase complex | No | Maybe | Exclusive to actinobacteria |
| Exospore formation | No | Yes | Exclusive to actinobacteria |
| HEH domain in Ku protein | No | No | Exclusive to actinobacteria |
Many of these traits argue for an actinobacterial role in eukaryogenesis but not the origin of archaea. This list of informative characters is taken from [16].