IMG/VR: a database of cultured and uncultured DNA Viruses and retroviruses

Nucleic Acids Res. 2017 Jan 4;45(D1):D457-D465. doi: 10.1093/nar/gkw1030. Epub 2016 Oct 30.


Viruses represent the most abundant life forms on the planet. Recent experimental and computational improvements have led to a dramatic increase in the number of viral genome sequences identified primarily from metagenomic samples. As a result of the expanding catalog of metagenomic viral sequences, there exists a need for a comprehensive computational platform integrating all these sequences with associated metadata and analytical tools. Here we present IMG/VR (, the largest publicly available database of 3908 isolate reference DNA viruses with 264 413 computationally identified viral contigs from >6000 ecologically diverse metagenomic samples. Approximately half of the viral contigs are grouped into genetically distinct quasi-species clusters. Microbial hosts are predicted for 20 000 viral sequences, revealing nine microbial phyla previously unreported to be infected by viruses. Viral sequences can be queried using a variety of associated metadata, including habitat type and geographic location of the samples, or taxonomic classification according to hallmark viral genes. IMG/VR has a user-friendly interface that allows users to interrogate all integrated data and interact by comparing with external sequences, thus serving as an essential resource in the viral genomics community.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • DNA Viruses / genetics*
  • Databases, Genetic*
  • Environmental Microbiology
  • Genome, Viral*
  • Genomics / methods*
  • Host-Pathogen Interactions
  • Metagenome
  • Metagenomics / methods*
  • Retroviridae / genetics*
  • Sequence Analysis, DNA
  • Software*