Hi,
I am using 5 samples pooled DNA Targeted sequencing data (Illumina FASTQ) and using BWA - GATK for mapping and variant calling. In variant calls (vcf files), I find that at aparticular position of genome, first base of the 900 reads (coverage is 1000X) showing mutation (889 out of 900 were showing altered base) but GATK gives very low QUAL score ~40, while highest QUAL in dataset is something about 20,000.
My question is first base is of high quality base calling and so high altered base count makes it good candidate of mutation. Why does GATK gives so much low QUAL score?
I am using 5 samples pooled DNA Targeted sequencing data (Illumina FASTQ) and using BWA - GATK for mapping and variant calling. In variant calls (vcf files), I find that at aparticular position of genome, first base of the 900 reads (coverage is 1000X) showing mutation (889 out of 900 were showing altered base) but GATK gives very low QUAL score ~40, while highest QUAL in dataset is something about 20,000.
My question is first base is of high quality base calling and so high altered base count makes it good candidate of mutation. Why does GATK gives so much low QUAL score?
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