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Store Structural Variants Into Vcf

Hi, after Represent Precise Deletion In Vcf, I've got some more questions about other structural variants in VCF, so I try to put them all into this post.

  • Duplication

                         123         456
    reference genome -----[           ]-------------------------------------------
                         123         456              789         1122
    sample genome    -----[           ]----------------[           ]--------------
    

    Here is example of duplication, but I don't know how to interpret POS and END. Would END be 456 in this example? Or 1122? And what about POS?

    I think with breakends it will look like this (let's say duplication occurs on chromosome 1):

    #CHROM  POS ID REF ALT      QUAL FILTER INFO
    1       788 .  .   .[1:123[ .    .      SVTYPE=BND;EVENT=DUP0
    1       789 .  .   ]1:456]. .    .      SVTYPE=BND;EVENT=DUP0
    

    But I also want to know how to use simpler way.

  • Translocation

                         123         456
    reference genome -----[           ]-------------------------------------------
                                                      789         1122
    sample genome    ----------------------------------[           ]--------------
    

    I think I can use entry about deletion and same entries like above for duplication:

    #CHROM  POS ID REF ALT      QUAL FILTER INFO
    1       123 .  .   .<DEL>   .    .      SVTYPE=DEL;END=456;SVLEN=-333;EVENT=TRANS0
    1       788 .  .   .[1:123[ .    .      SVTYPE=BND;EVENT=TRANS0
    1       789 .  .   ]1:456]. .    .      SVTYPE=BND;EVENT=TRANS0
    

    But there is maybe another way how to store this.

  • Insertion

    What if I don't know precise sequence of insertion? I know that I have to type <INS> into ALT column, but what about this sequence? What first come to my mind is to create new meta information, something like this:

    ##INFO=<ID=ISEQ,Number=1,Type=String,Description=“Imprecise inserted sequence”>
    

    Then I can store it into INFO column and maybe create another meta informations which describe confidence about begin and end of this sequence:

    ##INFO=<ID=CINSBEGIN,Number=1,Type=Integer,Description=“Confidence begin of inserted sequence”>
    ##INFO=<ID=CINSEND,Number=1,Type=Integer,Description=“Confidence end of inserted sequence”>
    

    Example:

    #CHROM  POS ID REF ALT      QUAL FILTER INFO
    1       123 .  .   .<INS>   .    .      SVTYPE=INS;END=123;ISEQ=ATTCGATCA;CINSBEGIN=2;CINSEND=1
    

    I can interpret it like insertion of these possible sequences: ATTCGATCA, TTCGATCA, TCGATCA, ATTCGATC, TTCGATC, TCGATC. So I am sure about insertion of sequence TCGATC, but there could be possible prefixes (A, AT) and sufixes (A). I hope I made it clear.

Thanks for all your help.

vcf

the terminology and definitions are unexpectedly complicated, it is quite surprising how many corner cases and ambiguities exist

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