Database Commons

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Database Profile

General information

Full name: ortholog groups with inparalogs
Description: The InParanoid database provides a user interface to orthologs inferred by the InParanoid algorithm.
Year founded: 2005
Last update: 2013-12-13
Version: v8.0
Real time : Checking...
Country/Region: Sweden
Data type:
Data object:
Database category:
Major organism:

Contact information

University/Institution: Stockholm University
Address: Science for Life Laboratory,Box 1031,SE-17121 Solna,Sweden
City: Solna
Country/Region: Sweden
Contact name (PI/Team): Erik L.L. Sonnhammer
Contact email (PI/Helpdesk):


InParanoid 8: orthology analysis between 273 proteomes, mostly eukaryotic. [PMID: 25429972]
Sonnhammer EL, Östlund G.

The InParanoid database ( provides a user interface to orthologs inferred by the InParanoid algorithm. As there are now international efforts to curate and standardize complete proteomes, we have switched to using these resources rather than gathering and curating the proteomes ourselves. InParanoid release 8 is based on the 66 reference proteomes that the 'Quest for Orthologs' community has agreed on using, plus 207 additional proteomes from the UniProt complete proteomes--in total 273 species. These represent 246 eukaryotes, 20 bacteria and seven archaea. Compared to the previous release, this increases the number of species by 173% and the number of pairwise species comparisons by 650%. In turn, the number of ortholog groups has increased by 423%. We present the contents and usages of InParanoid 8, and a detailed analysis of how the proteome content has changed since the previous release. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Nucleic Acids Res. 2015:43(Database issue) | 202 Citations (from Europe PMC, 2021-06-19)
InParanoid 7: new algorithms and tools for eukaryotic orthology analysis. [PMID: 19892828]
Ostlund G, Schmitt T, Forslund K, Köstler T, Messina DN, Roopra S, Frings O, Sonnhammer EL.

The InParanoid project gathers proteomes of completely sequenced eukaryotic species plus Escherichia coli and calculates pairwise ortholog relationships among them. The new release 7.0 of the database has grown by an order of magnitude over the previous version and now includes 100 species and their collective 1.3 million proteins organized into 42.7 million pairwise ortholog groups. The InParanoid algorithm itself has been revised and is now both more specific and sensitive. Based on results from our recent benchmarking of low-complexity filters in homology assignment, a two-pass BLAST approach was developed that makes use of high-precision compositional score matrix adjustment, but avoids the alignment truncation that sometimes follows. We have also updated the InParanoid web site ( Several features have been added, the response times have been improved and the site now sports a new, clearer look. As the number of ortholog databases has grown, it has become difficult to compare among these resources due to a lack of standardized source data and incompatible representations of ortholog relationships. To facilitate data exchange and comparisons among ortholog databases, we have developed and are making available two XML schemas: SeqXML for the input sequences and OrthoXML for the output ortholog clusters.

Nucleic Acids Res. 2010:38(Database issue) | 362 Citations (from Europe PMC, 2021-06-19)
InParanoid 6: eukaryotic ortholog clusters with inparalogs. [PMID: 18055500]
Berglund AC, Sjölund E, Ostlund G, Sonnhammer EL.

The InParanoid eukaryotic ortholog database ( has been updated to version 6 and is now based on 35 species. We collected all available 'complete' eukaryotic proteomes and Escherichia coli, and calculated ortholog groups for all 595 species pairs using the InParanoid program. This resulted in 2 642 187 pairwise ortholog groups in total. The orthology-based species relations are presented in an orthophylogram. InParanoid clusters contain one or more orthologs from each of the two species. Multiple orthologs in the same species, i.e. inparalogs, result from gene duplications after the species divergence. A new InParanoid website has been developed which is optimized for speed both for users and for updating the system. The XML output format has been improved for efficient processing of the InParanoid ortholog clusters.

Nucleic Acids Res. 2008:36(Database issue) | 135 Citations (from Europe PMC, 2021-06-19)
Inparanoid: a comprehensive database of eukaryotic orthologs. [PMID: 15608241]
O'Brien KP, Remm M, Sonnhammer EL.

The Inparanoid eukaryotic ortholog database ( is a collection of pairwise ortholog groups between 17 whole genomes; Anopheles gambiae, Caenorhabditis briggsae, Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, Takifugu rubripes, Gallus gallus, Homo sapiens, Mus musculus, Pan troglodytes, Rattus norvegicus, Oryza sativa, Plasmodium falciparum, Arabidopsis thaliana, Escherichia coli, Saccharomyces cerevisiae and Schizosaccharomyces pombe. Complete proteomes for these genomes were derived from Ensembl and UniProt and compared pairwise using Blast, followed by a clustering step using the Inparanoid program. An Inparanoid cluster is seeded by a reciprocally best-matching ortholog pair, around which inparalogs (should they exist) are gathered independently, while outparalogs are excluded. The ortholog clusters can be searched on the website using Ensembl gene/protein or UniProt identifiers, annotation text or by Blast alignment against our protein datasets. The entire dataset can be downloaded, as can the Inparanoid program itself.

Nucleic Acids Res. 2005:33(Database issue) | 412 Citations (from Europe PMC, 2021-06-19)


All databases:
139/5061 (97.273%)
Phylogeny and homology:
7/216 (97.222%)
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Record metadata

Created on: 2015-06-20
Curated by:
Dong Zou [2018-03-06]
Chunlei Yu [2016-04-17]
Chunlei Yu [2016-03-31]
Chunlei Yu [2015-11-20]
Chunlei Yu [2015-07-14]
Chunlei Yu [2015-06-29]