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velvet website  

Sequence assembler for very short reads.

Velvet is a de novo genomic assembler specially designed for short read sequencing technologies, such as Solexa or 454, developed by Daniel Zerbino and Ewan Birney at the European Bioinformatics Institute (EMBL-EBI), near Cambridge, in the United Kingdom.

Velvet currently takes in short read sequences, removes errors then produces high quality unique contigs. It then uses paired-end read and long read information, when available, to retrieve the repeated areas between contigs.

In the Velvet module version 1.2.06 MetaVelvet-1.1.01 is made available. There are two versions compiled, meta-velvetg (using a max kmer of 31) and meta-velvetg_MAX99 (using a max kmer of 99). There are also multiple contributed scripts available in the same location as the velvet binaries.

However, in the Velvet module version 1.2.07 only the contributed scripts are present. MetaVelvet-1.2.01 is now provided by its own "metavelvet" module.

Required Modules

modules documentation


  • velvet

System Variables

  • HPC_{{#uppercase:velvet}}_DIR - installation directory
  • HPC_VELVET_BIN - same as above.

Additional Information

  1. The user manual is available here.
  1. If you use one of the OpenMP versions of velvet, you must set the enviroment variables OMP_NUM_THREADS and OMP_THREAD_LIMIT to the appropriate value based on the processor request in your submission script. For example if you use #PBS -l nodes=1:ppn=8 in your script, also include export OMP_NUM_THREADS=7; export OMP_THREAD_LIMIT=8 (for a bash script) in the script itself (see sample script below and/or the user manual for more information).
  2. Please file a bugzilla request if you need an executable with different compile-time options such as color space, different kmers, LONGSEQUENCES, etc.

PBS Script Examples

See the Velvet_PBS page for velvet PBS script examples.