# MappingQualityZero

Count of all reads with MAPQ = 0 across all samples

## Overview

This anotation gives you the count of all reads that have MAPQ = 0 across all samples. The count of reads with MAPQ0 can be used for quality control; high counts typically indicate regions where it is difficult to make confident calls.

### Related annotations

• MappingQualityZeroBySample gives the count of reads with MAPQ=0 for each individual sample.
• LowMQ gives the proportion of reads with low mapping quality (MAPQ below 10, including 0).