BamUtil: stats

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Revision as of 14:47, 7 October 2011 by Mktrost (talk | contribs) (Update Stats)
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Overview of the stats function of bamUtil

The stats option on the BamUtil executable generates the specified statistics on a SAM/BAM file.

Parameters

	Required Parameters:
		--in : the SAM/BAM file to calculate stats for
	Types of Statistics that can be generated:
		--basic       : Turn on basic statistic generation
		--qual        : Generate a count for each quality (displayed as non-phred quality)
		--phred       : Generate a count for each quality (displayed as phred quality)
		--baseQC      : Write per base statistics to the specified file.
	Optional Parameters:
		--maxNumReads : Maximum number of reads to process
		                Defaults to -1 to indicate all reads.
		--unmapped    : Only process unmapped reads (requires a bamIndex file)
		--bamIndex    : The path/name of the bam index file
		                (if required and not specified, uses the --in value + ".bai")
		--regionList  : File containing the region list chr<tab>start_pos<tab>end<pos>.
		                Positions are 0 based and the end_pos is not included in the region.
		                Uses bamIndex.
		--minMapQual  : The minimum mapping quality for filtering reads in the baseQC stats.
		--dbsnp       : The dbSnp file of positions to exclude from baseQC analysis.
		--noeof       : Do not expect an EOF block on a bam file.
		--params      : Print the parameter settings

For all types of statistics, the bam file used is specified by --in.

The optional parameters are also used for all types of statistics.

Usage:

	./bam stats --in <inputFile> [--basic] [--qual] [--phred] [--baseQC <outputFileName>] [--maxNumReads <maxNum>] [--unmapped] [--bamIndex <bamIndexFile>] [--regionList <regFileName>] [--minMapQual <minMapQ>] [--dbsnp <dbsnpFile>] [--noeof] [--params]


Types of Statistics

Basic

Prints summary statistics for the file:

  • TotalReads - # of reads that are in the file
  • MappedReads - # of reads marked mapped in the flag
  • PairedReads - # of reads marked paired in the flag
  • ProperPair - # of reads marked paired AND proper paired in the flag
  • DuplicateReads - # of reads marked duplicate in the flag
  • QCFailureReads - # of reads marked QC failure in the flag
  • MappingRate(%) - # of reads marked mapped in the flag / TotalReads
  • PairedReads(%) - # of reads marked paired in the flag / TotalReads
  • ProperPair(%) - # of reads marked paired AND proper paired in the flag / TotalReads
  • DupRate(%) - # of reads marked duplicate in the flag / TotalReads
  • QCFailRate(%) - # of reads marked QC failure in the flag / TotalReads
  • TotalBases - # of bases in all reads
  • BasesInMappedReads - # of bases in reads marked mapped in the flag

Qual/Phred

Prints a count of the number of times each quality value appears in the file.

  • phred Displays Quality as phred integers [0-93]
  • qual Displays Quality as non-phred integers (phred + 33) [33-126]


BaseQC

The baseQC option generates the following statistics:

A read spans a position if the read starts at or before the position, ends at or after the position and the position is not a clip. CIGAR operations allowed for the position are M/X/=/D/N.

Currently there is no special logic to exclude positions/reads where the reference base is 'N' or the read base is 'N'.


BaseQC Output

There are two output options for BaseQC.

  1. Percentages
  2. Straight Counts

Percentage-Based Output Format

Order/Descriptions:

Field Description Excludes Duplicates, QC Failures Excludes Unmapped Excludes MapQual = 255 Excludes Below Min MapQual
chrom Chromosome/reference name string from the SAM/BAM
chromStart 0-based start position
chromEnd 0-based end position (always 1 greater than start and not included in this region)
Depth # of reads that are mapped with acceptable Mapping Quality, and are not duplicates or QC failures X X X
Q20Bases # of bases at this position with a base quality (from the read) of Q20 or higher X X X
Q20BasesPct(%) Q20Bases / Depth X X X
TotalReads # of reads that span this position
MappedBases # of reads marked mapped in the flag X X
MappingRate(%) MappedBases / TotalReads X X
MapRate_MQPass(%) # of reads that have a Mapping Quality >= a minimum Mapping Quality / TotalReads X X
ZeroMapQual(%) # of reads that have a Mapping Quality of 0 / TotalReads X X
MapQual<10(%) # of reads that have a Mapping Quality < 10 / TotalReads X X
PairedReads(%) # of reads marked paired in the flag / TotalReads X X
ProperPaired(%) # of reads marked paired AND proper paired in the flag / TotalReads X X
DupRate(%) # of reads marked duplicate in the flag / TotalReads
QCFailRate(%) # of reads marked QC failure in the flag / TotalReads
AverageMapQuality sum of included mapping qualities / AverageMapQualCount X X X
AverageMapQualCount # of mapping qualities in AverageMapQuality X X X

This output does not include a MapQual255 count in version 1.0.

Sample Output
chrom	chromStart	chromEnd	Depth	Q20Bases	Q20BasesPct(%)	TotalReads	MappedBases	MappingRate(%)	MapRate_MQPass(%)	ZeroMapQual(%)	MapQual<10(%)	PairedReads(%)	ProperPaired(%)	DupRate(%)	QCFailRate(%)	AverageMapQuality	AverageMapQualCount
1	100	101	2	2	100.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	11.000	3
1	101	102	2	0	0.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	11.000	3
1	102	103	0	0	0.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	0.000	0
1	103	104	0	0	0.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	0.000	0
1	104	105	2	0	0.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	11.000	3
1	105	106	2	2	100.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	11.000	3
1	110	111	0	0	0.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	0.000	0
1	111	112	2	2	100.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	11.000	3
1	112	113	2	2	100.000	3	3	100.000	66.667	33.333	66.667	100.000	0.000	0.000	0.000	11.000	3
1	10012	10013	14	0	0.000	42	33	78.571	52.381	26.190	52.381	85.714	35.714	14.286	14.286	11.000	21
1	10013	10014	14	10	71.429	39	30	76.923	51.282	25.641	51.282	84.615	38.462	15.385	15.385	11.000	21
1	10023	10024	0	0	0.000	39	30	76.923	51.282	25.641	51.282	84.615	38.462	15.385	15.385	0.000	0
1	10024	10025	14	12	85.714	39	30	76.923	51.282	25.641	51.282	84.615	38.462	15.385	15.385	11.000	21

Count-Based Output Format

Field Description Excludes Duplicates, QC Failures Excludes Unmapped Excludes MapQual = 255 Excludes Below Min MapQual
chrom Chromosome/reference name string from the SAM/BAM
chromStart 0-based start position
chromEnd 0-based end position (always 1 greater than start and not included in this region)
TotalReads # of reads that span this position
Dups # of reads marked duplicate in the flag
QCFail # of reads marked QC failure in the flag
Mapped # of reads marked mapped in the flag X X
Paired # of reads marked paired in the flag X X
ProperPaired # of reads marked paired AND proper paired in the flag X X
ZeroMapQual # of reads that have a Mapping Quality of 0 X X
MapQual<10(%) # of reads that have a Mapping Quality < 10 X X
MapQual255 # of reads that have a Mapping Quality = 255 X X
PassMapQual # of reads that have a Mapping Quality >= a minimum Mapping Quality X X
AverageMapQuality sum of included mapping qualities / AverageMapQualCount X X X
AverageMapQualCount # of mapping qualities in AverageMapQuality X X X
Depth # of reads that are mapped with acceptable Mapping Quality, and are not duplicates or QC failures X X X
Q20Bases # of bases at this position with a base quality (from the read) of Q20 or higher X X X