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samtools-depth(1)	     Bioinformatics tools	     samtools-depth(1)

NAME
       samtools	depth -	computes the read depth	at each	position or region

SYNOPSIS
       samtools	       depth	    [options]	     [in1.sam|in1.bam|in1.cram
       [in2.sam|in2.bam|in2.cram] [...]]

DESCRIPTION
       Computes	the depth at each position or region.

OPTIONS
       -a      Output all positions (including those with zero depth)

       -a -a, -aa
	       Output absolutely all positions,	including unused reference se-
	       quences.	 Note that when	used in	conjunction with  a  BED  file
	       the  -a option may sometimes operate as if -aa was specified if
	       the reference sequence has coverage outside of the region spec-
	       ified in	the BED	file.

       -b FILE Compute depth at	list of	positions or regions in	specified  BED
	       FILE.  []

       -f FILE Use  the	 BAM files specified in	the FILE (a file of filenames,
	       one file	per line) []

       -H      Write a comment line showing column names at the	 beginning  of
	       the  output.  The names are CHROM, POS, and then	the input file
	       name for	each depth column.  If one of  the  inputs  came  from
	       stdin, the name "-" will	be used	for the	corresponding column.

       -l INT  Ignore  reads shorter than INT.	This is	the number of bases in
	       the sequence, minus any soft clips.

       -m, -d INT
	       (Deprecated since 1.13)	This  option  previously  limited  the
	       depth  to  a maximum value.  It is still	accepted as an option,
	       but ignored.

	       Note for	single files, the behaviour of old samtools  depth  -J
	       -q0  -d	INT FILE is identical to samtools mpileup -A -Q0 -x -d
	       INT FILE	| cut -f 1,2,4

       -o FILE Write output to FILE.  Using "-"	for FILE will send the	output
	       to stdout (also the default if this option is not used).

       -q, --min-BQ INT
	       Only count reads	with base quality greater than or equal	to INT

       -Q, --min-MQ INT
	       Only  count reads with mapping quality greater than or equal to
	       INT

       -r CHR:FROM-TO
	       Only report depth in specified region.

       -X      If this option is set, it will allow the	user to	 specify  cus-
	       tomized index file location(s) if the data folder does not con-
	       tain any	index file. Example usage: samtools depth [options] -X
	       /data_folder/in1.bam    [/data_folder/in2.bam	[...]]	  /in-
	       dex_folder/index1.bai [/index_folder/index2.bai [...]]

       -g FLAGS
	       By default, reads that have any of the flags UNMAP,  SECONDARY,
	       QCFAIL,	or DUP set are skipped.	To include these reads back in
	       the analysis, use this option together with the desired flag or
	       flag combination.  FLAGS	can be specified in hex	 by  beginning
	       with `0x' (i.e. /^0x[0-9A-F]+/),	in octal by beginning with `0'
	       (i.e.  /^0[0-7]+/),  as a decimal number	not beginning with '0'
	       or as a comma-separated list of flag names. [0]

	       For a list of flag names	see samtools-flags(1).

       -G FLAGS, --excl-flags FLAGS
	       Discard reads that have any of the  flags  specified  by	 FLAGS
	       set.   FLAGS  are  specified  as	for the	-g option. [UNMAP,SEC-
	       ONDARY,QCFAIL,DUP]

       --incl-flags FLAGS
	       Only include reads with at least	one bit	set in	FLAGS  present
	       in  the	FLAG field.  FLAGS are specified as for	the -g option.
	       [0]

       --require-flags FLAGS
	       Only include reads with all bits	set in FLAGS  present  in  the
	       FLAG field.  FLAGS are specified	as for the -g option. [0]

       -J      Include reads with deletions in depth computation.

       -s      For  the	 overlapping  section  of  a read pair,	count only the
	       bases of	the first read.	 Note this algorithm changed  in  1.13
	       so the results may differ slightly to older releases.

CAVEATS
       It  may	appear that "samtools depth" is	simply "samtools mpileup" with
       some of the columns removed, and	indeed earlier versions	of  this  com-
       mand  were  just	this.  However both then and now there are subtle dif-
       ferences	in parameters which make  the  two  not	 entirely  comparable.
       Differences, other than the obvious speed benefits, include:

       o Deletions  (CIGAR  element  "D")  are	ignored	by default in "depth".
	 These may be counted by  adding  the  -J  option.   "Mpileup"	always
	 counts	the deleted bases, and has no option to	toggle this.

       o Beware	 there	are  idiosyncrasies in option naming.  Specifically -q
	 and -Q	options	 have  their  meanings	swapped	 between  "depth"  and
	 "mpileup".

       o The  removal of overlapping sequences (option -s) is on by default in
	 "mpileup" and off by default in "depth".   Additionally  the  overlap
	 removal  algorithm differs, giving subtle changes when	Ns are present
	 in the	sequence.  Also	any paired read	is considered for overlap  re-
	 moval	by  "depth",  rather  than only	those with the properly-paired
	 flag set ("mpileup").	See above for a	more detailed description.

       o The default minimum quality  value  is	 0  for	 "depth"  and  13  for
	 "mpileup".

       o Specifying  multiple BAMs will	produce	one depth column per file with
	 "depth", but these are	merged in "mpileup".

       o "Depth" doesn't have a	maximum	depth limit, while "mpileup"  defaults
	 to a maximum of 8000.

       o If  a	reference  is specified	to "mpileup" the BAQ algorithm will be
	 used to adjust	quality	values,	although it can	be disabled.   "Depth"
	 never uses BAQ.

AUTHOR
       Written by Heng Li and James Bonfield from the Sanger Institute.

SEE ALSO
       samtools(1),   samtools-mpileup(1),   samtools-coverage(1),   samtools-
       sort(1)

       Samtools	website: <http://www.htslib.org/>

samtools-1.21		       12 September 2024	     samtools-depth(1)

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