picard picard CollectSequencingArtifactMetrics

picard CollectSequencingArtifactMetrics

Identifier: TL_e24fa5_49.c8


Collect metrics to quantify single-base sequencing artifacts. This tool examines two sources of sequencing errors associated with hybrid selection protocols. These errors are divided into two broad categories, pre-adapter and bait-bias. Pre-adapter errors can arise from laboratory manipulations of a nucleic acid sample e.g. shearing and occur prior to the ligation of adapters for PCR amplification (hence the name pre-adapter). Bait-bias artifacts occur during or after the target selection step, and correlate with substitution rates that are 'biased', or higher for sites having one base on the reference/positive strand relative to sites having the complementary base on that strand. For example, during the target selection step, a (G>T) artifact might result in a higher substitution rate at sites with a G on the positive strand (and C on the negative), relative to sites with the flip (C positive)/(G negative). This is known as the 'G-Ref' artifact. For additional information on these types of artifacts, please see the corresponding GATK dictionary entries on bait-bias and pre-adapter artifacts. This tool produces four files; summary and detail metrics files for both pre-adapter and bait-bias artifacts. The detailed metrics show the error rates for each type of base substitution within every possible triplet base configuration. Error rates associated with these substitutions are Phred-scaled and provided as quality scores, the lower the value, the more likely it is that an alternate base call is due to an artifact. The summary metrics provide likelihood information on the 'worst-case' errors.


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