SVmerge¶
SVmerge groups structural variants from a VCF file by calculating a distance matrix, then finding connected components of a graph in which the nodes are the variants and edges exist when the distances are below the specified maximum values.
The program steps through a set of structural variants, calculating distances to other nearby variants by comparing their alternate haplotypes. The program then reports clusters of variants, and prints a VCF file of “unique” variants, where the variant reported in the VCF record is a randomly-chosen representative from the largest cluster (or a randomly selected largest cluster, in the case of a tie among cluster sizes) of exactly matching variants.
Alternatively, a file of previously-calculated distances can be provided with the –distance_file option, and the clustering can be skipped with the option –skip_clusters.
NOTE: SVmerge only clusters and merges sequence-specific variants, i.e., structural variants with ATGCN sequences for their REF and ALT alleles, or deletions with a valid “END” INFO tag. These variants will be printed as singletons unless the –seqspecific option is specified (see below).
Usage¶
svanalyzer merge --ref <reference FASTA file> --variants <VCF-formatted variant file> --prefix <prefix for output files>
svanalyzer merge --ref <reference FASTA file> --fof <file of paths to VCF-formatted variant files> --prefix <prefix for output files>
Options¶
| Option | Description |
|---|---|
| –help|–manual | Display documentation. |
| –ref | The reference FASTA file for the supplied VCF file or files. |
| –variants | A VCF-formatted file of (possibly equivalent) variants to merge. |
| –fof | A file of paths to VCF-formatted files to merge. |
| –prefix | Prefix for output file names (default “merged”) |
| –maxdist | Maximum distance between pairs of variants to perform comparison for potential merging (default: 2000) |
| –reldist | Maximum allowable edit distance, normalized by the mean length of larger allele for the two variants, in an alignment used to merge two variants (default: 0.2) |
| –relsizediff | Maximum allowable alt allele size difference, normalized by the mean length of larger allele for the two variants, to merge two variants (default: 0.2) |
| –relshift | Maximum allowable shift, normalized by the mean length of the larger allele for the two variants, in an alignment used to merge two variants (default: 0.2) |
| –seqspecific | With this option, SVmerge will fail to print out any SV that does not have an ATGCN sequence for REF and ALT in the input VCF files. |