I generated one vcf file from 4 different bam-files (4 samples) and had a look at some variants in the vcf and in the IGViewer (IGV).
I don't understand why the value for DP in the formatstring (i.e. for one sample) often differs (is less) from what I can see in the IGV. Meaning, vcf tells me a certain variant in a certain sample has read depth (DP) of 3 but I see more reads covering that position in the IGV. I thought that maybe bases of bad quality where left out, but reads and base qualities are good. Is there any other measure that I don't know yet which filters out certain reads / bases from being reported in the DP field in the format string (and consequently is not used for genotype assignment)?
Any hint is appreciated.
I don't understand why the value for DP in the formatstring (i.e. for one sample) often differs (is less) from what I can see in the IGV. Meaning, vcf tells me a certain variant in a certain sample has read depth (DP) of 3 but I see more reads covering that position in the IGV. I thought that maybe bases of bad quality where left out, but reads and base qualities are good. Is there any other measure that I don't know yet which filters out certain reads / bases from being reported in the DP field in the format string (and consequently is not used for genotype assignment)?
Any hint is appreciated.
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