bgzip library

[leomrtns]

the VCF files are compressed with the zlib library, but bcftools complains about it:

$ bcftools merge -o merge.vcf *.vcf.gz
Failed to open 1701018_ERR1701018.vcf.gz: not compressed with bgzip

bcftools also complained about unordered entries (e.g. location 5 before location 4), which may occur on overlapping HTs (more than one HT may map to same location in reference genome, and in this case the alternatives have variants in different flanking location, not on HT itself).