COG Guess

Clusters of Orthologous Groups tentative fitting

COG Database Query Page
Similarity search in COG DataBase: function and COG category guess

Similarity searches are performed with GAPPED-BLAST (BLAST 2.2.3 [May-13-2002] NCBI, Altschul et al., 1997, Nucleic Acids Res. 25:3389-3402)

For cogs overview:
Tatusov, R.L., Koonin, E.V., and Lipman, D.J. (1997). Science 278: 631-637.
Tatusov, et al. (2001). Nucleic Acids Res 29: 22-28.

 Genomapper BLAST  psiBLAST  Mulalbla  Multalin  Genes & Genomes  BLAST (restricted)  Genome Guts  COG Guess  INTERPROScan  CDD search  Pattern search  Sequence Patterns  COG Trees  Genome Syntenizer


Enter your sequence (fasta) or a gene number (eg: PAB0255) here:




 Search domain  :



 Display full alignements in graphics  

(*) A query sequence is BLASTed vs . the COG database, then results from this search are compiled according to
several criteria (see below in red) in order to give an estimation - a guess- of the most probable category and COG
number of the query. Please take into account the following :
- True fitting of proteins in the COG database are made by COGNITOR program and E. Koonin group members
- As this procedure is completely automatic, it is important to discard potentially wrong assignments by a careful
examination of sequence alignments.
Results STATUS legend :
good = match length > 50 % of query sequence length, number of best COG matches > 1/4 total number of matched COGs
suspect: MH = multiple hits in COG database, number of best COG matches < 1/4 total number of matched COGs
suspect: LH = Less than 3 Hits in COG database
suspect: HSP = match length <= 40 % of orf length
suspect: Pn = expect value (Pn) for best match is near cut off value (1e-07)
suspect: %id = % identity of best hits is less than 25% over matched length
normal = all the rest



Blast version 2 Advanced Options


Expectation value (E)




Filter query sequence
(DUST with blastn, SEG with others)

True False

Perform gapped alignment

True False 

Cost to open a gap


One-line descriptions (V)


Cost to extend a gap


Alignments to show (B)


X dropoff value
for gapped alignment (in bits)


Threshold for extending hits


 Genomapper BLAST  psiBLAST  Mulalbla  Multalin  Genes & Genomes  BLAST (restricted)  Genome Guts  COG Guess  INTERPROScan  CDD search  Pattern search  Sequence Patterns  COG Trees  Genome Syntenizer




Last revision on Wednesday March 03 2010

DataBase administrator

Laboratoire de Biologie Moléculaire du Gène chez les Extrêmophiles.