Problem
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Diagnose Targets identifies holes in the coverage of a targetted experiment, but it only reports them doesn't list the actual missing loci
Solution
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This commit implements an optional intervals file output listing the exact loci that did not pass filters
Itemized changes
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* Cache callable statuses (to avoid recalculation)
* Add functionality to output missing intervals
* Implement new tool to qualify the missing intervals (QualifyMissingIntervals) by gc content, size, type of missing coverage and origin (coding sequence, intron, ...)