Hi there,
I used VarScan.v2.4.3.jar mpileup2snp to call mutations with -min-coverage=100 and --min-var-freq= 0.01 and I got some weird variants. For example, one mutation for the output is :
21 42848562 . G C . PASS ADP=866;WT=0;HET=1;HOM=0;NC=0 GT:GQ:SDP:DP:RD:AD:FREQ:PVAL:RBQ:ABQ:RDF:RDR:ADF:ADR 0/1:0:866:866:6:5:45.45%:9.8E-1:36:34:4:2:3:2
Usually, DP=RD+AD=RDF+RDR+ADF+ADR and FREQ=AD/DP=(ADF+ADR)/(RDF+RDF+ADF+ADR), but in this case RD+AD=11, not equal to DP=866. Frequency should be 5/866=0.6%, also not equal to 45.45%.
How to explain this variant? Which value should I choose to filter? Does anyone have any idea?
Thanks so much! Rui
My first option would be to visually inspect the BAM with IGV or similar and see if I can make sense of the numbers.