bigwigCompare

This tool compares two bigWig files based on the number of mapped reads. To compare the bigWig files, the genome is partitioned into bins of equal size, then the number of reads found in each BAM file are counted per bin and finally a summary value is reported. This value can be the ratio of the number of readsper bin, the log2 of the ratio, the sum or the difference.

usage: bigwigCompare -b1 sample1.bw -b2 sample2.bw -o log2.bw
help: bigwigCompare -h / bigwigCompare --help

Named Arguments

--bigwig1, -b1

Bigwig file 1. Usually the file for the treatment.

--bigwig2, -b2

Bigwig file 2. Usually the file for the control.

--scaleFactors

Set this parameter to multipy the bigwig values by a constant. The format is scaleFactor1:scaleFactor2. For example 0.7:1 to scale the first bigwig file by 0.7 while not scaling the second bigwig file

--pseudocount

A small number to avoid x/0. Only useful together with –operation log2 or –operation ratio. You can specify different values as pseudocounts for the numerator and the denominator by providing two values (the first value is used as the numerator pseudocount and the second the denominator pseudocount). (Default: 1)

--skipZeroOverZero

Skip bins where BOTH BAM files lack coverage. This is determined BEFORE any applicable pseudocount is added.

--operation

Possible choices: log2, ratio, subtract, add, mean, reciprocal_ratio, first, second

The default is to output the log2ratio of the two samples. The reciprocal ratio returns the the negative of the inverse of the ratio if the ratio is less than 0. The resulting values are interpreted as negative fold changes. Instead of performing a computation using both files, the scaled signal can alternatively be output for the first or second file using the ‘–operation first’ or ‘–operation second’ (Default: “log2”)

--skipNonCoveredRegions, --skipNAs

This parameter determines if non-covered regions (regions without a score) in the bigWig files should be skipped. The default is to treat those regions as having a value of zero. The decision to skip non-covered regions depends on the interpretation of the data. Non-covered regions in a bigWig file may represent repetitive regions that should be skipped. Alternatively, the interpretation of non-covered regions as zeros may be wrong and this option should be used

--fixedStep

Write out all bins (of size –binSize) instead of merging neighbouring bins with equal values.

Optional arguments

--version

show program’s version number and exit

--binSize, -bs

Size of the bins, in bases, for the output of the bigwig/bedgraph file. (Default: 50)

--region, -r

Region of the genome to limit the operation to - this is useful when testing parameters to reduce the computing time. The format is chr:start:end, for example –region chr10 or –region chr10:456700:891000.

--blackListFileName, -bl

A BED or GTF file containing regions that should be excluded from all analyses. Currently this works by rejecting genomic chunks that happen to overlap an entry. Consequently, for BAM files, if a read partially overlaps a blacklisted region or a fragment spans over it, then the read/fragment might still be considered. Please note that you should adjust the effective genome size, if relevant.

--numberOfProcessors, -p

Number of processors to use. Type “max/2” to use half the maximum number of processors or “max” to use all available processors. (Default: 1)

--verbose, -v

Set to see processing messages.

Output

--outFileName, -o

Output file name.

--outFileFormat, -of

Possible choices: bigwig, bedgraph

Output file type. Either “bigwig” or “bedgraph”.

deepTools Galaxy.

code @ github.