What is COG classification?
The database of Clusters of Orthologous Groups of proteins (COGs) is an attempt on a phylogenetic classification of the proteins encoded in 21 complete genomes of bacteria, archaea and eukaryotes (http://www.ncbi.nlm.nih.gov/COG ).
What are clusters of orthologous groups?
Database Description The database of Clusters of Orthologous Groups of proteins (COGs) is an attempt on phylogenetic classification of the proteins encoded in complete genomes. Each COGs includes proteins that are inferred to be orthologs (direct evolutionary counterparts).
How many COGs in the human genome?
The COG collection currently consists of 138,458 proteins, which form 4873 COGs and comprise 75% of the 185,505 (predicted) proteins encoded in 66 genomes of unicellular organisms.
What does orthologous mean?
Orthologous are homologous genes where a gene diverges after a speciation event, but the gene and its main function are conserved. If a gene is duplicated in a species, the resulting duplicated genes are paralogs of each other, even though over time they might become different in sequence composition and function.
What is COG genes?
COGs stands for Clusters of Orthologous Genes. The database was initially created in 1997 (Tatusov et al., PMID: 9381173) followed by several updates, most recently in 2014 (Galperin et al., PMID: 25428365). The current update includes complete genomes of 1,187 bacteria and 122 archaea that map into 1,234 genera.
What is eggNOG Mapper?
eggNOG-mapper is a tool for functional annotation of large sets of sequences based on fast orthology assignments using precomputed clusters and phylogenies from the eggNOG database. Orthology assignment is ideally suited for functional inference.
What is the difference between an ortholog and a Paralog?
Orthologous genes are the homologous genes found in different species due to separation by speciation. Meanwhile, paralogous genes are the homologous genes found within a single species due to duplication. So, this is the key difference between orthologous and paralogous genes.
What is a cog analysis?
A center of gravity (COG) is a source of power that provides moral or physical strength, freedom of action, or will to act. 1 Analyzing COGs provides a means of focusing friendly efforts, both offensively and defensively. There are a number of tools and techniques available to identify and analyze COGs.