If no AD in mutect or freebayes, then setting AF to nil, and further skipping such variants
If no AD in mutect or freebayes, then setting AF to nil, and further skipping such variants

AstraZeneca-NGS/VarDict,chapmanb/VarDict,chapmanb/VarDict,AstraZeneca-NGS/VarDict,AstraZeneca-NGS/VarDict,chapmanb/VarDict