---
name: "hmmer"
section: "1"
platform: "linux"
package: "hmmer"
version: "3.4+dfsg-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/hmmer"
---

# hmmer(1)

profile HMMs for biological sequence analysis

## NAME

HMMER - profile HMMs for biological sequence analysis

## SYNOPSIS

```
hmmalign
  Align sequences to a profile
hmmbuild
  Construct profiles from multiple sequence alignments
hmmconvert
  Convert profile file to various formats
hmmemit
  Sample sequences from a profile
hmmfetch
  Retrieve profiles from a file
hmmlogo
  Produce a conservation logo graphic from a profile
hmmpgmd
  Daemon for database search web services
hmmpress
  Prepare a profile database for hmmscan
hmmscan
  Search sequence(s) against a profile database
hmmsearch
  Search profile(s) against a sequence database
hmmsim
  Collect profile score distributions on random sequences
hmmstat
  Summary statistics for a profile file
jackhmmer
  Iteratively search sequence(s) against a sequence database
makehmmerdb
  build nhmmer database from a sequence file
nhmmer
  Search DNA/RNA queries against a DNA/RNA sequence database
nhmmscan
  Search DNA/RNA sequence(s) against a DNA/RNA profile database
phmmer
  Search protein sequence(s) against a protein sequence database
alimask
  Calculate and add column mask to a multiple sequence alignment
```

## DESCRIPTION

HMMER is a suite of several programs for biological sequence alignment and database homology search. It uses probabilistic models called "profile hidden Markov models" (profile HMMs) to represent the likely evolutionary homologs of a single sequence or a multiple alignment of a sequence family. A main avenue of research is to improve the evolutionary predictive models in HMMER to be able to recognize and accurately align increasingly remote homologs, distant in time.

HMMER is also used as an organizational tool, to group the exponentially growing number of biological sequences into a vastly smaller set of well-annotated sequence families. New sequences can be annotated by comparison against curated sequence family databases of prebuilt HMMER profiles, in addition or instead of comparison to the entire sequence database. Databases such as Pfam, SMART, and TIGRfams, among others, are based on this principle.

HMMER is used in three main modes: to search a sequence database for new homologs of a sequence or a sequence family; to search a profile database (like Pfam) to find what known family a query sequence belongs to, or what domains it has; and to automatically construct large multiple alignments (i.e. with an effectively unlimited number of sequences) using a profile representative of a sequence family.

Suppose you have a multiple sequence alignment of a sequence family of interest, and you want to search a sequence database for additional homologs. The **hmmbuild** program builds profile(s) from multiple alignment(s).  The **hmmsearch** program searches protein profile(s) against a protein sequence database, and  **nhmmer** searches nucleotide profile(s) against a nucleotide sequence database.

Suppose you have a single sequence of interest, and you want to search a sequence database for additional homologs. The **phmmer** program searches a single protein sequence against a protein sequence database. The **jackhmmer** program does the same thing but iteratively -- homologs detected in a previous round are incorporated into a new profile, and the new profile is searched again.  **phmmer** is used like BLASTP, and  **jackhmmer** is used like a protein PSI-BLAST. The **nhmmer** program searches a single nucleotide sequence against a nucleotide sequence.

Suppose you have sequence(s) that you want to analyze using a HMMER-based profile HMM database like Pfam (http://pfam.sanger.ac.uk). The **hmmpress** program formats a profile HMM flatfile (such as the file you would download from Pfam) into a HMMER binary database. The  **hmmscan** program searches protein sequence(s) against that database. The  **nhmmscan** program can similarly search nucleotide sequence(s) against a pressed database of nucleotide profiles, such as from  Dfam (http://dfam.janelia.org).

Suppose you want to align lots of sequences. You can construct a manageably small alignment of a representative set of sequences, build a profile with **hmmbuild**, and use the **hmmalign** program to align any number of sequences to that profile.

HMMER also includes some auxiliary tools for working with large profile databases. **hmmfetch** fetches one or more profiles from a database. **hmmstat** prints summary statistics about a profile file.

For compatibility with other profile software and previous versions of HMMER, the **hmmconvert** program converts profiles to a few other formats. We intend to add more support for other formats over time.

The **hmmemit** program generates (simulates) "homologous" sequences by sampling from a profile. It can also generate a "consensus" sequence.

The  **hmmsim** program is a simulator used for collecting statistics about score distributions on random sequences.

Each program has its own man page.

## SEE ALSO

This is a summary man page for the entire HMMER3 package. See individual man pages  \[[**hmmbuild**(1)](/hmmbuild/1.md), for example\] for usage, options, and description of each program in the package.

For complete documentation, see the user guide that came with your HMMER distribution (Userguide.pdf); or see the HMMER web page (http://hmmer.org/).

## COPYRIGHT

```
Copyright (C) 2023 Howard Hughes Medical Institute.
Freely distributed under the BSD open source license.
```

For additional information on copyright and licensing, see the file called COPYRIGHT in your HMMER source distribution, or see the HMMER web page  (http://hmmer.org/).

## AUTHOR

```
http://eddylab.org
```