binReads {chromstaR} | R Documentation

## Convert aligned reads from various file formats into read counts in equidistant bins

### Description

Convert aligned reads in .bam or .bed(.gz) format into read counts in equidistant windows.

### Usage

    binReads(file, experiment.table = NULL, ID = NULL, assembly,
      bamindex = file, chromosomes = NULL, pairedEndReads = FALSE,
      min.mapq = 10, remove.duplicate.reads = TRUE, max.fragment.width = 1000,
      blacklist = NULL, binsizes = 1000, stepsizes = binsizes/2,
      reads.per.bin = NULL, bins = NULL, variable.width.reference = NULL,
      use.bamsignals = TRUE, format = NULL)

### Arguments

`file` | A file with aligned reads. Alternatively a `GRanges-class` with aligned reads.
`experiment.table` | An `experiment.table` containing the supplied `file`. This is necessary to uniquely identify the file in later steps of the workflow. Set to `NULL` if you don't have it (not recommended).
`ID` | Optional ID to select a row from the `experiment.table`. Only necessary if the experiment table contains the same file in multiple positions in column 'file'.
`assembly` | Please see `fetchExtendedChromInfoFromUCSC` for available assemblies. Only necessary when importing BED files. BAM files are handled automatically. Alternatively a data.frame with columns 'chromosome' and 'length'.
`bamindex` | BAM index file. Can be specified without the .bai ending. If the index file does not exist it will be created and a warning is issued.
`chromosomes` | If only a subset of the chromosomes should be binned, specify them here.
`pairedEndReads` | Set to `TRUE` if you have paired-end reads in your BAM files (not implemented for BED files).
`min.mapq` | Minimum mapping quality when importing from BAM files. Set `min.mapq=0` to keep all reads.
`remove.duplicate.reads` | A logical indicating whether or not duplicate reads should be removed.
`max.fragment.width` | Maximum allowed fragment length. This is to filter out erroneously wrong fragments due to mapping errors of paired end reads.
`blacklist` | A `GRanges-class` or a bed(.gz) file with blacklisted regions. Reads falling into those regions will be discarded.
`binsizes` | An integer vector specifying the bin sizes to use.
`stepsizes` | An integer vector specifying the step size. One number can be given for each element in `binsizes`, `reads.per.bin` and `bins` (in that order).
`reads.per.bin` | Approximate number of desired reads per bin. The bin size will be selected accordingly.
`bins` | A `GRanges-class` or a named `list()` with `GRanges-class` containing precalculated bins produced by `fixedWidthBins` or `variableWidthBins`. Names of the list must correspond to the binsize. If the list is unnamed, an attempt is made to automatically determine the binsize.
`variable.width.reference` | A BAM file that is used as reference to produce variable width bins. See `variableWidthBins` for details.
`use.bamsignals` | If `TRUE` the bamsignals package is used for parsing of BAM files. This gives tremendous speed advantage for only one binsize but linearly increases for multiple binsizes, while `use.bamsignals=FALSE` has a binsize dependent runtime and might be faster if many binsizes are calculated.
`format` | One of `c('bed','bam','GRanges',NULL)`. With `NULL` the format is determined automatically from the file ending.

### Details

Convert aligned reads from .bam or .bed(.gz) files into read counts in equidistant windows (bins). This function uses `GenomicRanges::countOverlaps` to calculate the read counts, or alternatively `bamsignals::bamProfile` if option `use.bamsignals` is set (only effective for .bam files).

### Value

If only one bin size was specified for option `binsizes`, the function returns a single `GRanges-class` object with meta data column 'counts' that contains the read count. If multiple `binsizes` were specified , the function returns a named `list()` of GRanges-class objects.

### Examples

    ## Get an example BAM file with ChIP-seq reads
    file <- system.file("extdata", "euratrans",
                       "lv-H3K27me3-BN-male-bio2-tech1.bam",
                        package="chromstaRData")
    ## Bin the file into bin size 1000bp
    data(rn4_chrominfo)
    data(experiment_table)
    binned <- binReads(file, experiment.table=experiment_table,
                      assembly=rn4_chrominfo, binsizes=1000,
                      stepsizes=500, chromosomes='chr12')
    print(binned)

[Package chromstaR version 1.8.1 Index]