/**
* Finds the adaptor boundary around the read and returns the first base inside the adaptor that
* is closest to the read boundary. If the read is in the positive strand, this is the first base
* after the end of the fragment (Picard calls it 'insert'), if the read is in the negative
* strand, this is the first base before the beginning of the fragment.
*
* <p>There are two cases we need to treat here:
*
* <p>1) Our read is in the reverse strand :
*
* <p><----------------------| * |--------------------->
*
* <p>in these cases, the adaptor boundary is at the mate start (minus one)
*
* <p>2) Our read is in the forward strand :
*
* <p>|----------------------> * <----------------------|
*
* <p>in these cases the adaptor boundary is at the start of the read plus the inferred insert
* size (plus one)
*
* @param read the read being tested for the adaptor boundary
* @return the reference coordinate for the adaptor boundary (effectively the first base IN the
* adaptor, closest to the read. NULL if the read is unmapped or the mate is mapped to another
* contig.
*/
public static Integer getAdaptorBoundary(final SAMRecord read) {
final int MAXIMUM_ADAPTOR_LENGTH = 8;
final int insertSize =
Math.abs(
read
.getInferredInsertSize()); // the inferred insert size can be negative if the mate
// is mapped before the read (so we take the absolute
// value)
if (insertSize == 0
|| read
.getReadUnmappedFlag()) // no adaptors in reads with mates in another chromosome or
// unmapped pairs
return null;
Integer
adaptorBoundary; // the reference coordinate for the adaptor boundary (effectively the first
// base IN the adaptor, closest to the read)
if (read.getReadNegativeStrandFlag())
adaptorBoundary = read.getMateAlignmentStart() - 1; // case 1 (see header)
else adaptorBoundary = read.getAlignmentStart() + insertSize + 1; // case 2 (see header)
if ((adaptorBoundary < read.getAlignmentStart() - MAXIMUM_ADAPTOR_LENGTH)
|| (adaptorBoundary > read.getAlignmentEnd() + MAXIMUM_ADAPTOR_LENGTH))
adaptorBoundary =
null; // we are being conservative by not allowing the adaptor boundary to go beyond what
// we belive is the maximum size of an adaptor
return adaptorBoundary;
}
private void collectReadData(final SAMRecord record, final ReferenceSequence ref) {
metrics.TOTAL_READS++;
readLengthHistogram.increment(record.getReadBases().length);
if (!record.getReadFailsVendorQualityCheckFlag()) {
metrics.PF_READS++;
if (isNoiseRead(record)) metrics.PF_NOISE_READS++;
if (record.getReadUnmappedFlag()) {
// If the read is unmapped see if it's adapter sequence
final byte[] readBases = record.getReadBases();
if (!(record instanceof BAMRecord)) StringUtil.toUpperCase(readBases);
if (isAdapterSequence(readBases)) {
this.adapterReads++;
}
} else if (doRefMetrics) {
metrics.PF_READS_ALIGNED++;
if (!record.getReadNegativeStrandFlag()) numPositiveStrand++;
if (record.getReadPairedFlag() && !record.getMateUnmappedFlag()) {
metrics.READS_ALIGNED_IN_PAIRS++;
// Check that both ends have mapq > minimum
final Integer mateMq = record.getIntegerAttribute("MQ");
if (mateMq == null
|| mateMq >= MAPPING_QUALITY_THRESOLD
&& record.getMappingQuality() >= MAPPING_QUALITY_THRESOLD) {
++this.chimerasDenominator;
// With both reads mapped we can see if this pair is chimeric
if (Math.abs(record.getInferredInsertSize()) > maxInsertSize
|| !record.getReferenceIndex().equals(record.getMateReferenceIndex())) {
++this.chimeras;
}
}
}
}
}
}