GBS adapters
GBS Barcode Generator
Genotyping by sequencing (GBS) is a simple highly-multiplexed system for constructing reduced representation libraries for the Illumina next-generation sequencing platform developed in the Buckler Lab at Cornell. Key components of the system are: reduced sample handling, fewer PCR and purification steps, no size fractionation and inexpensive barcoding. They use restriction enzymes to reduce genome complexity and avoid the repetitive fraction of the genome.
A paper on the technique is published by Elshire et al in PLOS-One. More information on the method and the authors can be found here.
One of the difficulties in developing this technology was the complexity of generating a lot of barcodes that generate high quality libraries. Since the sequenced fragments all contain an enzyme recognition site this leads to identical nucleotides directly after the barcode if one uses one length of barcodes.
In the context of my PhD project at NIOO KNAW I followed a course at the Buckler lab. I decided to contribute by developing a script for generating Barcoded adapters satisfying the following criteria:
- Barcodes ( ligated to rescriction fragments) do not recreate enzyme restriction site.
- Every barcode differs from all other barcodes by at least 3 mutational steps.
- Barcodes can be modulated in length between 4 and 10 (possibly more) bases.
- The balance of nucleotides at every position in the barcodes is maintained as much as possible.
- Mononucleotide runs are not allowed by default. The threshold can be set by a parameter.
- Smaller Barcodes do not nest in larger barcodes, thus avoiding confusion in downstream bioinformatics.
- The script produces an identical output for identical queries, thus allowing for standardization across labs
Please file tickets for all possible bugs and feature requests here.
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DISCLAIMER
This software is provided “as is,” without warranty of any kind, express or implied. In no event shall Deena Bioinformatics or Thomas van Gurp be held liable for any direct, indirect, incidental, special or consequential damages arising out of the use of or inability to use this software.
