Changes

     to the left while keeping the length of all its alleles constant.   

     to the left while keeping the length of all its alleles constant.   

The following figure shows examples of an unnormalized short tandem repeat which is a special class of indels. The colour of the text is synchronized to the variant it is describing in the figure.

The following figure shows examples of an unnormalized short tandem repeat which is a special class of indels. The color of the text is synchronized to the variant that is described in the figure.

* <span style="color:#ff0000">The representation of variants in a VCF file requires that no alleles in the REF and ALT field are represented with an empty string (empty allele). The red indel is an illegal VCF representation.</span>

* <span style="color:#ff0000">The representation of variants in a VCF file requires that no alleles in the REF and ALT field are represented with an empty string (empty allele). The red indel has an illegal VCF representation.</span>

* <span style="color:#008000"> The green variant is not left aligned as you can prefix an A nucleotide on the left side of the variant's alleles and truncate the C on the right side of the variant's alleles.  It is however parsimonious. </span>

* <span style="color:#008000"> The green variant is not left aligned as you can prefix an A nucleotide on the left side of the variant's alleles and truncate the C on the right side of the variant's alleles.  It is however parsimonious. </span>

* <span style="color:#F9A908"> The orange variant is left aligned but is not right parsimonious.</span>

* <span style="color:#F9A908"> The orange variant is left aligned but is not right parsimonious.</span>