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walaj / bxtools

Tools for analyzing 10X Genomics data
MIT License
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genomics sequencing tenxgenomics

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bxtools - Tools for analyzing 10X genomics data

License: MIT

Note: bxtools is an emerging project. If you find an operation that you need that may be in the scope of bxtools, please submit an issue report or pull request with the suggested functionality. We are looking for community suggestions for what we might include.

Table of contents

Installation

git clone --recursive https://github.com/walaj/bxtools
cd bxtools
./configure
make 
make install

Description

bxtools is a set of light-weight command line tools for analyzing 10X genomics data. It is built to take care of low-level type operations in a 10X-specific way by accounting for the BX tag in 10X data.

Components

Split

Split a BAM file by the BX tag.

## split a BAM into individual BAMs (called test.<bx>.bam). Don't output tags with < 10 reads
bxtools split $bam -a test -m 10 > counts.tsv

## split a portion of a BAM 
samtools view -h $bam 1:1,000,000-2,000,000 | bxtools split - -a test > counts.tsv

## just get the BX counts and sort by prevalence
bxtools split $bam -x | sort -n -k 2,2 > counts.tsv

Stats

Collect BX-level statistics from a 10X BAM

bxtools stats $bam > stats.tsv
## output columns: BX, read count, median insert size, median mapq, median AS.

To summarize based on another tag, use -t. E.g. : bxtools stats -t MI $bam

Tile

Collect BX-level read counts on a tiled genome

## default is 1kb tiles, across entire genome
bxtools tile $bam > counts.bed

## input bed to check (e.g. chr1 only)
samtools view -h $bam 1:1-250,000,000 | bxtools tile - -b chr1.tiles.bed > chr1.tiles.counts.bed

Relabel

Move the BX barcodes from the BX tag (e.g. BX:ACTTACCGA) to the read name (e.g. qname_ACTTACCGA)

VERBOSE=-v ## print progress
bxtools relabel $bam $VERBOSE > relabeled.bam

Mol

Get the minimum molecular footprint on the genome as BED file for each MI tag. The minimal footprint is defined from the minimum start position to the maximum end position of all reads sharing an MI tag. Throws an error message if detects the same MI tag on multiple chromosomes.

The output BED format is chr, start, end, MI, BX, read_count

bxtools mol $bam > mol_footprint.bed

Convert

Switch the alignment chromosome with the BX tag. This is a hack to allow a 10X BAM to be sorted and indexed by BX tag, rather than coordinate. Useful for rapid lookup of all BX reads from a particular BX. Note that this switches "-" for "_" to make query possible with samtools view. This also requires a two-pass solution. The first loop is to get all of the unique BX tags to build the new BAM header. The second makes the switches. This means that streaming from stdin is not available.

bxtools convert $bam | samtools sort - -o bx_sorted.bam
samtools index bx_sorted.bam
samtools view AGTCCAAGTCGGAAGT_1

Example recipes

Get BX level coverage in 2kb bins across genome, ignore low-frequency tags

## make a list of bad tags (freq < 100)
samtools view -h $bam 1:1-10,000,000 | bxtools split - -x | awk '$2 < 100' | cut -f1 > excluded_list.txt

## get the coverage, while excluding bad tags (grep: -F literal, -f file, -v exclude)
samtools view -h $bam 1:1-10,000,000 | grep -v -F -f excluded_list.txt | bxtools tile - -w 2000 > bxcov.bed

Attributions

This project is developed and maintained by Jeremiah Wala (jwala@broadinstitute.org)

Analysis suggestions and 10X support