The original TIGRFAMs database was a research project of the J. Craig Venter Institute. TIGRFAMs, short for The Institute for Genomic Research's database of protein families, is a collection of manually curated protein families focusing primarily on prokaryotic sequences. It consists of hidden Markov models (HMMs), multiple sequence alignments, Gene Ontology (GO) terminology, cross-references to related models in TIGRFAMs and other databases, and pointers to literature.

The TIGRFAMs data were transferred in April 2018 to the National Center for Biotechnology Information (NCBI), which now holds the creative commons license to this data and is responsible for maintaining and distributing this intellectual property. NCBI will redistribute TIGRFAMs using a data interchange format that allows the original source to submit new data for inclusion in future releases, should they want to.

Release 15.0 of TIGRFAMs (4488 families, September 16 2014) continues to be available from the J. Craig Venter Institute. That release is also incorporated in the NCBI's Conserved Domain Database (CDD), as noted in the description of CDD's source databases.

The most recent version of TIGRFAMs includes additional enhancements made to the data, and is available from the NCBI FTP site. The enhancements include changes such as adjustment of score threshold values and improved product names.

The references listed below provide details about the TIGRFAMs project and should be cited when using any version of the TIGRFAMs data.
  The TIGRFAMs data are made available under a Creative Commons Attribution-ShareAlike 4.0 license, as described in the licensing terms for TIGRFAMs (https://ftp.ncbi.nlm.nih.gov/hmm/TIGRFAMs/license_and_availability.txt).

References: citing TIGRFAMs
  Haft DH, Selengut JD, Richter RA, Harkins D, Basu MK, Beck E. TIGRFAMs and Genome Properties in 2013. Nucleic Acids Res. 2013 Jan;41(Database issue):D387-95. doi: 10.1093/nar/gks1234. Epub 2012 Nov 28. [PubMed PMID: 23197656] [Full Text at Oxford Academic] Click here to read
  Selengut JD, Haft DH, Davidsen T, Ganapathy A, Gwinn-Giglio M, Nelson WC, Richter AR, White O. TIGRFAMs and Genome Properties: tools for the assignment of molecular function and biological process in prokaryotic genomes. Nucleic Acids Res. 2007 Jan;35(Database issue):D260-4. Epub 2006 Dec 6. [PubMed PMID: 17151080] [Full Text at Oxford Academic] Click here to read
  Haft DH, Selengut JD, White O. The TIGRFAMs database of protein families. Nucleic Acids Res. 2003 Jan 1;31(1):371-3. [PubMed PMID: 12520025] [Full Text in PubMed Central] Click here to read
  Haft DH, Loftus BJ, Richardson DL, Yang F, Eisen JA, Paulsen IT, White O. TIGRFAMs: a protein family resource for the functional identification of proteins. Nucleic Acids Res. 2001 Jan 1;29(1):41-3. [PubMed PMID: 11125044] [Full Text in PubMed Central] Click here to read

A separate publications page lists additional articles about the NCBI Conserved Domains and Protein Classification resources.

Revised 20 July 2018