vcRoot.add("POS", vc.getStart());
vcRoot.add("ID", vc.getID());
vcRoot.add("REF", vc.getReference());
vcRoot.add("ALT", vc.getAlternateAlleles());
vcRoot.add("QUAL", vc.hasLog10PError() ? vc.getLog10PError() * -10 : VCFConstants.MISSING_VALUE_v4);
vcRoot.add("FILTER", ! vc.filtersWereApplied() // needs null to differentiate between PASS and .
? VCFConstants.MISSING_VALUE_v4
: ( vc.getFilters().isEmpty() ? VCFConstants.PASSES_FILTERS_v4 : vc.getFilters()) );
// add info fields
for (Map.Entry<String, Object> attribute : vc.getAttributes().entrySet()) {