COG0491 is a COG (Clusters of Orthologous Groups, a catalog of ortholog-group gene families) entry that the central discoveries digest names, alongside COG0468 and COG0443, as one of the top-ranked functionally unknown ortholog groups 1.
Distribution and evidence status
In the full pangenome analysis of 27,690 species (NB11b), species counts for functionally dark gene ortholog groups range from 1 to 27,482, with a median of 135. More than half of these dark ortholog groups are pan-bacterial, present in thousands of species across multiple phyla. The digest describes COG0491, COG0468 and COG0443 as present in virtually all sequenced bacterial genomes yet having zero functional evidence. It reads this as showing that functional dark matter is a fundamental limitation in understanding broadly conserved biology, not a minor annotation gap 1.
In the functional dark matter project’s ranking, COG0491 sits at rank 3. It spans 27,393 species and 142 phyla, at the “kingdom” level, and is classified as a “true knowledge gap” with a reported score of 23.9. The report annotates it as “Pan-bacterial, zero evidence across all inference layers” 2. “Zero evidence” refers to the inference layers that project used. It is not an established absence of function. That makes this a prioritization signal for experimental characterization, not a functional finding 2.
Related
- cog0468 and cog0443 are the other top-ranked unknowns named alongside COG0491 1
- experimental-prioritization-of-functional-dark-matter covers how ranked unknowns such as COG0491 are prioritized for experiments 2
- Functional Dark Matter — Experimentally Prioritized Novel Genetic Systems and discoveries are the source summaries 2,1