eggNOG v4.0: nested orthology inference across 3686 organisms

Research output: Contribution to journalJournal articleResearchpeer-review

  • Sean Powell
  • Kristoffer Forslund
  • Damian Milosz Szklarczyk
  • Kalliopi Trachana
  • Alexander Roth
  • Jaime Huerta-Cepas
  • Toni Gabaldón
  • Thomas Rattei
  • Chris Creevey
  • Michael Kuhn
  • Jensen, Lars Juhl
  • Christian von Mering
  • Peer Bork
With the increasing availability of various 'omics data, high-quality orthology assignment is crucial for evolutionary and functional genomics studies. We here present the fourth version of the eggNOG database (available at that derives nonsupervised orthologous groups (NOGs) from complete genomes, and then applies a comprehensive characterization and analysis pipeline to the resulting gene families. Compared with the previous version, we have more than tripled the underlying species set to cover 3686 organisms, keeping track with genome project completions while prioritizing the inclusion of high-quality genomes to minimize error propagation from incomplete proteome sets. Major technological advances include (i) a robust and scalable procedure for the identification and inclusion of high-quality genomes, (ii) provision of orthologous groups for 107 different taxonomic levels compared with 41 in eggNOGv3, (iii) identification and annotation of particularly closely related orthologous groups, facilitating analysis of related gene families, (iv) improvements of the clustering and functional annotation approach, (v) adoption of a revised tree building procedure based on the multiple alignments generated during the process and (vi) implementation of quality control procedures throughout the entire pipeline. As in previous versions, eggNOGv4 provides multiple sequence alignments and maximum-likelihood trees, as well as broad functional annotation. Users can access the complete database of orthologous groups via a web interface, as well as through bulk download.
Original languageEnglish
JournalNucleic Acids Research
Issue numberD1
Pages (from-to)D231-D239
Number of pages9
Publication statusPublished - 1 Dec 2013

ID: 91131868