
VersionMap is used to convert genomic data between different genome assembly versions.
The first three fields in each feature line are required:
1. chrom - name of the chromosome or scaffold with the 'Chr' prefix
(i.e. Chr01, Chr10).
2. chromStart - Start position of the feature in standard
chromosomal coordinates (i.e. first base is 0).
3. chromEnd - End position of the feature in standard chromosomal
coordinates.
VCF (variant call format) is a flexible and extendable
line-oriented text format: