Identify Variants (WES)
The Identify Variants (WES) template workflow takes sequencing reads as input and returns identified variants as part of a Track List.
Sequencing reads provided as input are initially mapped to the human reference sequence. This is followed by the removal of duplicate mapped reads (to reduce biases introduced by target enrichment). The resulting read mapping is analyzed by the Structural Variant Caller to infer indels and other structural variants from unaligned end read patterns. Subsequently, the mapping is realigned, guided by the indels detected by the Structural Variant Caller. The locally realigned read mapping is analyzed by the Low Frequency Variant Detection tool. The Low Frequency Variant Detection tool produces a track of unfiltered variants; these are subjected to a number of post filters to remove variants that are likely due to artifacts or noise. The variants called by the Low Frequency Variant Detection tool that pass the post filtering criteria can be found in the Identified variants track. Variants inferred by the Structural Variant Caller, and not detected by the Low Frequency Variant Detection tool, are also subjected to a number of post filters; those that pass the post filter criteria can be found in the Indels indirect evidence track.
In addition, a targeted region report is created to inspect the overall coverage and mapping specificity in the targeted regions.
Before starting the workflow, you will need to import in the CLC Workbench a file with the genomic regions targeted by the amplicon or hybridization kit. Such a file (a BED or GFF file) is usually available from the vendor of the enrichment kit and sequencing machine. Use the Import | Tracks tool to import it in your Navigation Area.
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