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How do I create a de novo assembly using Velvet

Velvet is a de novo assembler intended for next generation reads. Velvet is ideal for assembling Illumina sequencing reads of bacterial genomes on a mid range Mac. With paired read data it produces very good contigs. For example a 7Mb genome with an N50 of 103kbp was produced from 16 million paired Illumina reads in one hour on a 16GB 2007 Mac Pro.

Velvet is much faster, at the cost of using slightly more RAM than SPAdes, but requires more tweaking of the Hash Value to achieve comparable assemblies..

For more details on using Velvet see the Velvet technical page

  1. Chose File | New | Assembly Project to create a new empty Assembly Project window.
  2. Click on the Add Reads tool bar button, then select the sequence files you wish to assemble and click on the Open button.
  3. Choose Analyze | Velvet to run the Velvet algorithm on all of the sequences in the project. Note that if no sequences are selected, Velvet will be run on ALL of the files in the project. However, if any sequences are selected then at least one reference sequence and at least a single file containing reads must be selected.
  4. In the Assembly Project window, double click on the contig to open it within the Contig Editor

Related Topics.

Assembler

Quick Start

Assembling sequences

Short Read Assembly

Base calling

SPAdes; de novo assembly

Align to reference.

How do I? - videos

Saving assemblies

Consensus