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SV Callers

MAVIS supports output from a wide-variety of SV callers. Assumptions are made for each tool based on interpretation of the output and the publications for each tool.

Configuring Conversions

Adding a conversion step to your MAVIS run is as simple as adding that section to the input JSON config.

The general structure of this section is as follows

{
    "convert": {
        "<ALIAS>": {
            "file_type": "<TOOL OUTPUT TYPE>",
            "name": "<TOOL NAME>",  // optional field for supported tools
            "inputs": [
                "/path/to/tool/output/file"
            ]
        }
    }
}

A full version of the input configuration file specification can be found in the configuration section.

Supported Tools

The tools and versions currently supported are given below. Versions listed indicate the version of the tool for which output files have been tested as input into MAVIS. MAVIS also supports a general VCF input.

SV Caller Version(s) Tested Files used as MAVIS input
BreakDancer (Chen, 2009) 1.4.5 Tools main output file(s)
BreakSeq (Abyzov, 2015) 2.2 work/breakseq.vcf.gz
Chimerascan (Iyer, 2011) 0.4.5 *.bedpe
CNVnator (Abyzov, 2011) 0.3.3 Tools main output file(s)
CuteSV (Jiang, 2020) 1.0.10 *.vcf
DeFuse (McPherson. 2011) 0.6.2 results/results.classify.tsv
DELLY (Rausch, 2012) 0.6.1 0.7.3 combined.vcf (converted from bcf)
Manta (Chen, 2016) 1.0.0 {diploidSV,somaticSV}.vcf
Pindel (Ye, 2009) 0.2.5b9 Tools main output file(s)
Sniffles (Sedlazeck, 2018) 1.0.12b *.vcf
STAR-Fusion (Haas, 2017) 1.4.0 star-fusion.fusion_predictions.abridged.tsv
Straglr (Chiu, 2021)
Strelka (Saunders, 2012) 1.0.6 passed.somatic.indels.vcf
Trans-ABySS (Robertson, 2010) 1.4.8 (custom) {indels/events_novel_exons,fusions/*}.tsv

Note

Trans-ABySS: The trans-abyss version used was an in-house dev version. However the output columns are compatible with 1.4.8 as that was the version branched from. Additionally, although indels can be used from both genome and transcriptome outputs of Trans-ABySS, it is recommended to only use the genome indel calls as the transcriptome indels calls (for versions tested) introduce a very high number of false positives. This will slow down validation. It is much faster to simply use the genome indels for both genome and transcriptome.

DELLY Post-processing

Some post-processing on the delly output files is generally done prior to input. The output BCF files are converted to a VCF file

bcftools concat -f /path/to/file/with/vcf/list --allow-overlaps --output-type v --output combined.vcf

General VCF inputs

Assuming that the tool outputting the VCF file follows standard conventions, then it is possible to use a general VCF conversion that is not tool-specific. Given the wide variety in content for VCF files, MAVIS makes a number of assumptions and the VCF conversion may not work for all VCFs. In general MAVIS follows the VCF 4.2 specification. If the input tool you are using differs, it would be better to use a custom conversion script.

Using the general VCF tool with a non-standard tool can be done as follows

{
    "convert": {
        "my_tool_alias": {
            "file_type": "vcf",
            "name": "my_tool",
            "inputs": ["/path/to/my_tool/output.vcf"]
        }
    }
}

Assumptions on non-standard INFO fields

  • PRECISE if given, Confidence intervals are ignored if given in favour of exact breakpoint calls using pos and END as the breakpoint positions
  • CT values if given are representative of the breakpoint orientations.
  • CHR2 is given for all interchromosomal events

Translating BND type Alt fields

There are four possible configurations for the alt field of a BND type structural variant based on the VCF specification. These correspond 1-1 to the orientation types for MAVIS translocation structural variants.

r = reference base/seq
u = untemplated sequence/alternate sequence
p = chromosome:position
alt format orients
ru[p[ LR
[p[ur RR
]p]ur RL
ru]p] LL

Custom Conversions

If there is a tool that is not yet supported by MAVIS and you would like it to be, you can either add a feature request to our GitHub page or tackle writing the conversion script yourself. Either way there are a few things you will need

  • A sample output from the tool in question
  • Tool metadata for the citation, version, etc

Logic Example - Chimerascan

The following is a description of how the conversion script for Chimerascan was generated. While this is a built-in conversion command now, the logic could also have been put in an external script. As mentioned above, there are a number of assumptions that had to be made about the tools output to convert it to the standard mavis format. Assumptions were then verified by reviewing at a series of called events in IGV. In the current example, Chimerascan output has six columns of interest that were used in the conversion

  • start3p
  • end3p
  • strand3p
  • start5p
  • end5p
  • strand5p

The above columns describe two segments which are joined. MAVIS requires the position of the join. It was assumed that the segments are always joined as a sense fusion. Using this assumption there are four logical cases to determine the position of the breakpoints.

i.e. the first case would be: If both strands are positive, then the end of the five-prime segment (end5p) is the first breakpoint and the start of the three-prime segment is the second breakpoint

Calling a Custom Conversion Script

Since MAVIS v3+ is run using snakemake the simplest way to incorporate your custom conversion scripts is to modify the Snakefile and add them as rules.