Orthologous Genes/Proteins

COG analysis

Clusters of Orthologous Groups - COG protein database was generated by comparing predicted and known proteins in all completely sequenced microbial genomes to infer sets of orthologs. Each COG consists of a group of proteins found to be orthologous across at least three lineages and likely corresponds to an ancient conserved domain. Sites which offer this analysis include:


RAST, BASys, and JGI IMG

RAST
(Reference: Aziz RK et al. 2008. BMC Genomics 9:75),
and BASys Bacterial Annotation System;
(Reference: Van Domselaar GH et al. 2005. Nucleic Acids Res. 33(Web Server issue):W455-459.)
and JGI IMG Integrated Microbial Genomes;
(Reference: Markowitz VM et al. 2014. Nucl. Acids Res. 42: D560-D567. )


Other sites:

EggNOG

EggNOG - A database of orthologous groups and functional annotation that derives Nonsupervised Orthologous Groups (NOGs) from complete genomes, and then applies a comprehensive characterization and analysis pipeline to the resulting gene families.
(Reference: Powell S et al. 2014. Nucleic Acids Res. 42 (D1): D231-D239)


KAAS

KAAS (KEGG Automatic Annotation Server) provides functional annotation of genes by BLAST or GHOST comparisons against the manually curated KEGG GENES database. The result contains KO (KEGG Orthology) assignments and automatically generated KEGG pathways.
(Reference: Moriya Y et al. 2007. Nucleic Acids Res. 35(Web Server issue):W182-185).


PHROGS

PHROGS - (PHage Remote Orthologous GroupS) - is a library of 38,880 viral protein families generated using a new clustering approach based on remote homology detection by HMM profile-profile comparisons.
(Reference: Tersian P et al. 2021. NAR Genom Bioinform. 3(3): lqab067).

Updated: December, 2025