rMATS turbo is the C/Cython version of rMATS (refer to http://rnaseq-mats.sourceforge.net). The major difference between rMATS turbo and rMATS is speed and space usage. rMATS turbo is 100 times faster and the output file is 1000 times smaller than rMATS. These advantages make analysis and storage of a large scale dataset easy and convenient.
Counting part | Statistical part | |
---|---|---|
Speed (C/Cython version vs Python version) | 20~100 times faster (one thread) | 300 times faster (6 threads) |
Storage usage (C/Cython version vs Python version) | 1000 times smaller | - |
Tested on Ubuntu (20.04 LTS)
- Python (3.6.12 or 2.7.15)
- Cython (0.29.21 or 0.29.15 for Python 2)
- BLAS, LAPACK
- GNU Scientific Library (GSL 2.5)
- GCC (>=5.4.0)
- gfortran (Fortran 77)
- CMake (3.15.4)
- PAIRADISE (optional)
- DARTS (optional)
- Samtools (optional)
- STAR (optional)
If the required dependencies are already installed, then rMATS can be built with:
./build_rmats
And then run with:
python rmats.py {arguments}
The build_rmats script usage is:
./build_rmats [--conda] [--no-paired-model] [--no-darts-model]
--conda: create a conda environment for Python and R dependencies
--no-paired-model: do not install dependencies for the paired model
--no-darts-model: do not install dependencies for the darts model
With --conda
build_rmats installs a conda environment that satisfies the required Python dependencies and also the R dependencies needed to use the paired model (PAIRADISE) and the DARTS model. The Python dependencies are listed in python_conda_requirements.txt and the R dependencies are handled using paired_model_conda_requirements.txt, darts_model_conda_requirements.txt, and install_r_deps.R after cloning the PAIRADISE and DARTS git repos.
run_rmats is a wrapper to call rmats.py with the conda environment used by build_rmats. It also sources setup_environment.sh which can be modified to handle other setup that might be needed before running rmats (such as Environment Modules).
If rMATS was built with ./build_rmats --conda
then it should be run with:
./run_rmats {arguments}
It takes about 30 minutes to install dependencies and build rMATS (as tested on an Ubuntu VM with 2 CPUs and 4 GB of memory)
test_rmats creates a conda environment and uses run_rmats to run the automated tests in tests/
Suppose there are 2 sample groups with 2 sets of paired read (R1, R2) FASTQ files per group. (fastq.gz
files can also be used)
- group 1 FASTQs
/path/to/1_1.R1.fastq
/path/to/1_1.R2.fastq
/path/to/1_2.R1.fastq
/path/to/1_2.R2.fastq
- group 2 FASTQs
/path/to/2_1.R1.fastq
/path/to/2_1.R2.fastq
/path/to/2_2.R1.fastq
/path/to/2_2.R2.fastq
Create txt files that will be used to pass this grouping of inputs to rMATS. The expected format is :
to separate paired reads and ,
to separate replicates.
/path/to/s1.txt
/path/to/1_1.R1.fastq:/path/to/1_1.R2.fastq,/path/to/1_2.R1.fastq:/path/to/1_2.R2.fastq
/path/to/s2.txt
/path/to/2_1.R1.fastq:/path/to/2_1.R2.fastq,/path/to/2_2.R1.fastq:/path/to/2_2.R2.fastq
Details about the remaining arguments are discussed in All arguments
run rMATS on this input with:
python rmats.py --s1 /path/to/s1.txt --s2 /path/to/s2.txt --gtf /path/to/the.gtf --bi /path/to/STAR_binary_index -t paired --readLength 50 --nthread 4 --od /path/to/output --tmp /path/to/tmp_output
rMATS will first process the FASTQ input into BAM files stored in the --tmp
directory. Then the splicing analysis will be performed.
Reads can be mapped independently of rMATS with any aligner and then the resulting BAM files can be used as input to rMATS. rMATS requires aligned reads to match --readLength unless --variable-read-length is given. rMATS also ignores alignments with soft or hard clipping unless --allow-clipping is given.
Suppose there are 2 sample groups with 2 BAM files per group.
- group 1 BAMs
/path/to/1_1.bam
/path/to/1_2.bam
- group 2 BAMs
/path/to/2_1.bam
/path/to/2_2.bam
Create txt files that will be used to pass this grouping of inputs to rMATS. The expected format is ,
to separate replicates.
/path/to/b1.txt
/path/to/1_1.bam,/path/to/1_2.bam
/path/to/b2.txt
/path/to/2_1.bam,/path/to/2_2.bam
Details about the remaining arguments are discussed in All arguments
run rMATS on this input with:
python rmats.py --b1 /path/to/b1.txt --b2 /path/to/b2.txt --gtf /path/to/the.gtf -t paired --readLength 50 --nthread 4 --od /path/to/output --tmp /path/to/tmp_output
rMATS analysis has two steps, prep and post. In the prep step, the input files are processed and a summary is saved to .rmats
files in the --tmp
directory. The .rmats
files track info from each BAM separately according to the full path of the BAM specified in the input .txt
file. In the post step, .rmats
files are read and the final output files are created.
The --task
argument allows the prep step of rMATS to be run independently for different subsets of input BAM files. Then the post step can be run on the independently generated .rmats
files. This allows the computation to be run at different times and/or on different machines.
Suppose we have 8 BAMs and two machines that each have 4 CPU threads. Each machine can run the prep step on 4 BAMs concurrently. Then the post step can be run on one of the machines.
Split the BAMs into two groups. The assignment of BAMs to prep steps does not restrict the choice of --b1
and --b2
for a later post step.
/path/to/prep1.txt
/path/to/1.bam,/path/to/2.bam,/path/to/3.bam,/path/to/4.bam
/path/to/prep2.txt
/path/to/5.bam,/path/to/6.bam,/path/to/7.bam,/path/to/8.bam
On machine 1 run the prep step with prep1.txt:
python rmats.py --b1 /path/to/prep1.txt --gtf /path/to/the.gtf -t paired --readLength 50 --nthread 4 --od /path/to/output --tmp /path/to/tmp_output_prep_1 --task prep
On machine 2 run the prep step with prep2.txt:
python rmats.py --b1 /path/to/prep2.txt --gtf /path/to/the.gtf -t paired --readLength 50 --nthread 4 --od /path/to/output --tmp /path/to/tmp_output_prep_2 --task prep
Split the BAMs into two groups. This split is for statistically comparing the two groups and does not need to reflect the split used in the prep steps
/path/to/post1.txt
/path/to/1.bam,/path/to/3.bam,/path/to/8.bam
/path/to/post2.txt
/path/to/2.bam,/path/to/4.bam,/path/to/5.bam,/path/to/6.bam,/path/to/7.bam
Copy the .rmats
files from the separate prep steps to a directory so that the post step can access all the prep data. The filenames have the format {datetime}_{id}.rmats
and the filenames may conflict for prep steps run concurrently. The script cp_with_prefix.py is provided to disambiguate the .rmats
filenames when copying to a shared directory:
python cp_with_prefix.py prep_1_ /path/to/tmp_output_post/ /path/to/tmp_output_prep_1/*.rmats
python cp_with_prefix.py prep_2_ /path/to/tmp_output_post/ /path/to/tmp_output_prep_2/*.rmats
On machine 1 run the post step:
python rmats.py --b1 /path/to/post1.txt --b2 /path/to/post2.txt --gtf /path/to/the.gtf -t paired --readLength 50 --nthread 4 --od /path/to/output --tmp /path/to/tmp_output_post --task post
The default statistical model considers the samples to be unpaired. The --paired-stats
flag can be used if each entry in --b1
is matched with its pair in --b2
. As an example, if there are three replicates where each replicate has paired "a" and "b" data, then b1.txt and b2.txt should look like:
/path/to/b1.txt
/path/to/pair_1_a.bam,/path/to/pair_2_a.bam,/path/to/pair_3_a.bam
/path/to/b2.txt
/path/to/pair_1_b.bam,/path/to/pair_2_b.bam,/path/to/pair_3_b.bam
The --paired-stats
flag can then be given so that the paired statistical model is used instead of the default unpaired model. As the paired model is running it updates a progress file under the --od
directory. As an example /path/to/od/tmp/JC_SE/pairadise_status.txt
is written when the paired model is producing the results for SE.MATS.JC.txt
.
The rMATS statistical model requires an event definition file (fromGTF.[AS].txt
) and a count file ({JC,JCEC}.raw.input.[AS].txt
) as input. Usually those files are created by the post step which also runs the statistical model to create the final output file ([AS].MATS.{JC,JCEC}.txt
). There may be situations where the event definitions and counts are already available and the statistical model can be run on those existing files with
python rmats.py --od /path/to/dir_with_existing_files --tmp /path/to/tmp_dir --task stat
One use case for --task stat
is when there are more than two groups to compare. For example, if there are 3 sample groups, then it is possible to compare each sample group to the other two (1 to 2, 1 to 3, 2 to 3). This can be done by first processing all the samples together using the usual rMATS pipeline
- Run the prep step for each BAM (can utilize multiple compute nodes)
- Combine all the prep results in a single post step (
--statoff
)
After all of the BAMs have been processed in this way, the output directory will contain the necessary fromGTF.[AS].txt
and {JC,JCEC}.raw.input.[AS].txt
files. The fromGTF.[AS].txt
files can be used "as is" for all comparisons involving the samples, but the information that is relevant to a specific comparison needs to be extracted from the {JC,JCEC}.raw.input.[AS].txt
files. This can be done using rMATS_P/prepare_stat_inputs.py. If there are 3 replicates in each of the 3 groups and they were provided in the --b1
argument of the post step in ascending order (group_1_rep_1, group_1_rep_2, ..., group_3_rep_3
) then the comparisons can be performed by
python rMATS_P/prepare_stat_inputs.py --new-output-dir /path/to/1_to_2_output --old-output-dir /path/to/combined_post_output --group-1-indices 0,1,2 --group-2-indices 3,4,5
python rmats.py --od /path/to/1_to_2_output --tmp /path/to/1_to_2_tmp --task stat
python rMATS_P/prepare_stat_inputs.py --new-output-dir /path/to/1_to_3_output --old-output-dir /path/to/combined_post_output --group-1-indices 0,1,2 --group-2-indices 6,7,8
python rmats.py --od /path/to/1_to_3_output --tmp /path/to/1_to_3_tmp --task stat
python rMATS_P/prepare_stat_inputs.py --new-output-dir /path/to/2_to_3_output --old-output-dir /path/to/combined_post_output --group-1-indices 3,4,5 --group-2-indices 6,7,8
python rmats.py --od /path/to/2_to_3_output --tmp /path/to/2_to_3_tmp --task stat
- The statistical comparison between the two input sample groups can be skipped with
--statoff
. It is also possible to use a single sample group (only--b1
or--s1
) when using--statoff
. - The number of replicates can differ between sample 1 and sample 2 (example: 3 BAMs in
--b1
and 1 BAM in--b2
) fastq.gz
files can be used with--s1
,--s2
. They will be automatically detected based on the.gz
extension and decompressed- A cluster environment can be utilized to run many prep steps concurrently and when the prep steps are finished a single post step can be run.
- When splitting the computation using
--task {prep, post}
, rMATS will consider all.rmats
files in the--tmp
directory when running the post step. The.rmats
files from multiple prep steps can be copied to a shared location for running the post step. Replacing--task post
in the command line that is going to be used for the post step with--task inte
will perform an integrity check to verify that the BAM filenames in--b1
and--b2
match 1-to-1 with the BAM filenames recorded in the.rmats
files in--tmp
. - The
.rmats
filenames from concurrently run prep steps may conflict. The script cp_with_prefix.py is provided to disambiguate the.rmats
filenames when copying to a shared directory. - The full path of the BAM files given in
--b1
and--b2
for the prep step must match the full paths given in the post step. Otherwise the lookup into the.rmats
file(s) will fail. As an example, if the full/path/to/1.bam
is used in the prep step, a relative path of just1.bam
cannot be used in the post step. - If analyzing a small data set,
--task both
can be used to perform the prep and post steps in a single run. --novelSS
is an experimental feature that allows splicing events to be detected that involve an unannotated splice site.--fixed-event-set
can be set to a directory containing thefromGTF.[AS].txt
files from a previous run of rMATS. The events in the provided files will be used directly instead of detecting events from the input reads. This can be used to run new data against the events detected from a previous rMATS run. ThefromGTF.[AS].txt
files can also be edited manually to specify a custom event set.--libType
options are based on TopHat--library-type
. Forfr-unstranded
, the strand of the alignment is not checked. Forfr-firststrand
andfr-secondstrand
, the strand is determined for each read and the strand is checked against the annotated strand for the gene. Forfr-firststrand
andfr-secondstrand
, paired reads must be aligned to opposite strands. Forfr-secondstrand
the aligned strand of the first read is used as the original strand. Forfr-firststrand
, the aligned strand of the first read is not used as the original strand and instead the other strand is used as the original. According to the salmon library formatfr-firststrand
is ISR andfr-secondstrand
is ISF
python rmats.py -h
usage: rmats.py [options]
optional arguments:
-h, --help show this help message and exit
--version show program's version number and exit
--gtf GTF An annotation of genes and transcripts in GTF format
--b1 B1 A text file containing a comma separated list of the
BAM files for sample_1. (Only if using BAM)
--b2 B2 A text file containing a comma separated list of the
BAM files for sample_2. (Only if using BAM)
--s1 S1 A text file containing a comma separated list of the
FASTQ files for sample_1. If using paired reads the
format is ":" to separate pairs and "," to separate
replicates. (Only if using fastq)
--s2 S2 A text file containing a comma separated list of the
FASTQ files for sample_2. If using paired reads the
format is ":" to separate pairs and "," to separate
replicates. (Only if using fastq)
--od OD The directory for final output from the post step
--tmp TMP The directory for intermediate output such as ".rmats"
files from the prep step
-t {paired,single} Type of read used in the analysis: either "paired" for
paired-end data or "single" for single-end data.
Default: paired
--libType {fr-unstranded,fr-firststrand,fr-secondstrand}
Library type. Use fr-firststrand or fr-secondstrand
for strand-specific data. Only relevant to the prep
step, not the post step. Default: fr-unstranded
--readLength READLENGTH
The length of each read. Required parameter, with the
value set according to the RNA-seq read length
--variable-read-length
Allow reads with lengths that differ from --readLength
to be processed. --readLength will still be used to
determine IncFormLen and SkipFormLen
--anchorLength ANCHORLENGTH
The "anchor length" or "overhang length" used when
counting the number of reads spanning splice
junctions. A minimum number of "anchor length"
nucleotides must be mapped to each end of a given
splice junction. The minimum value is 1 and the
default value is set to 1 to make use of all possible
splice junction reads.
--tophatAnchor TOPHATANCHOR
The "anchor length" or "overhang length" used in the
aligner. At least "anchor length" nucleotides must be
mapped to each end of a given splice junction. The
default is 1. (Only if using fastq)
--bi BINDEX The directory name of the STAR binary indices (name of
the directory that contains the suffix array file).
(Only if using fastq)
--nthread NTHREAD The number of threads. The optimal number of threads
should be equal to the number of CPU cores. Default: 1
--tstat TSTAT The number of threads for the statistical model. If
not set then the value of --nthread is used
--cstat CSTAT The cutoff splicing difference. The cutoff used in the
null hypothesis test for differential alternative
splicing. The default is 0.0001 for 0.01% difference.
Valid: 0 <= cutoff < 1. Does not apply to the paired
stats model
--task {prep,post,both,inte,stat}
Specify which step(s) of rMATS-turbo to run. Default:
both. prep: preprocess BAM files and generate .rmats
files. post: load .rmats files into memory, detect and
count alternative splicing events, and calculate P
value (if not --statoff). both: prep + post. inte
(integrity): check that the BAM filenames recorded by
the prep task(s) match the BAM filenames for the
current command line. stat: run statistical test on
existing output files
--statoff Skip the statistical analysis
--paired-stats Use the paired stats model
--darts-model Use the DARTS statistical model
--darts-cutoff DARTS_CUTOFF
The cutoff of delta-PSI in the DARTS model. The output
posterior probability is P(abs(delta_psi) > cutoff).
The default is 0.05
--novelSS Enable detection of novel splice sites (unannotated
splice sites). Default is no detection of novel splice
sites
--mil MIL Minimum Intron Length. Only impacts --novelSS
behavior. Default: 50
--mel MEL Maximum Exon Length. Only impacts --novelSS behavior.
Default: 500
--allow-clipping Allow alignments with soft or hard clipping to be used
--fixed-event-set FIXED_EVENT_SET
A directory containing fromGTF.[AS].txt files to be
used instead of detecting a new set of events
--individual-counts Output individualCounts.[AS_Event].txt files and add
the individual count columns to [AS_Event].MATS.JC.txt
In rMATS-turbo, each alternative splicing pattern has a corresponding set of output files. In the filename templates below, [AS_Event]
is replaced by one of the five basic alternative splicing patterns: skipped exon (SE), alternative 5' splice sites (A5SS), alternative 3' splice sites (A3SS), mutually exclusive exons (MXE), or retained intron (RI). As shown in the diagram, the number of supporting reads can be counted by the junction reads only (JC) or by both the junction and exon reads (JCEC). The output files from different counting methods are also indicated in the file name.
--od
contains the final output files from the post step:
[AS_Event].MATS.JC.txt
: Final output that contains the list of events and read counts. Only splice junction reads are counted.[AS_Event].MATS.JCEC.txt
: Final output that contains the list of events and read counts. Both splice junction reads and exon body reads are counted.fromGTF.[AS_Event].txt
: All identified alternative splicing (AS) events derived from the GTF file and RNA-seq data.fromGTF.novelJunction.[AS_Event].txt
: AS events derived from novel combinations of splice sites annotated in the GTF file. Does not include events with an unannotated splice site.fromGTF.novelSpliceSite.[AS_Event].txt
: This file contains only events that include an unannotated splice site. Only relevant if--novelSS
is enabled.JC.raw.input.[AS_Event].txt
: Event counts including only reads that span junctions defined by rMATS.JCEC.raw.input.[AS_Event].txt
: Event counts including both reads that span junctions defined by rMATS and reads that do not cross an exon boundary.individualCounts.[AS_Event].txt
: The breakdown of individual counts which contribute to the inclusion and skipping counts (only if run with--individual-counts
)- Shared columns:
ID
: rMATS event idGeneID
: Gene idgeneSymbol
: Gene namechr
: Chromosomestrand
: Strand of the geneIJC_SAMPLE_1
: Inclusion counts for sample 1. Replicates are comma separatedSJC_SAMPLE_1
: Skipping counts for sample 1. Replicates are comma separatedIJC_SAMPLE_2
: Inclusion counts for sample 2. Replicates are comma separatedSJC_SAMPLE_2
: Skipping counts for sample 2. Replicates are comma separatedIncFormLen
: Length of inclusion form, used for normalizationSkipFormLen
: Length of skipping form, used for normalizationPValue
: Significance of splicing difference between the two sample groups. (Only available if the statistical model is on)FDR
: False Discovery Rate calculated from p-value. (Only available if statistical model is on)IncLevel1
: Inclusion level for sample 1. Replicates are comma separated. Calculated from normalized countsIncLevel2
: Inclusion level for sample 2. Replicates are comma separated. Calculated from normalized countsIncLevelDifference
: average(IncLevel1) - average(IncLevel2)
- Event specific columns (event coordinates and counts):
- SE:
exonStart_0base
exonEnd
upstreamES
upstreamEE
downstreamES
downstreamEE
upstream_to_target_count
target_to_downstream_count
target_count
upstream_to_downstream_count
- The inclusion form includes the target exon (
exonStart_0base
,exonEnd
)
- The inclusion form includes the target exon (
- MXE:
1stExonStart_0base
1stExonEnd
2ndExonStart_0base
2ndExonEnd
upstreamES
upstreamEE
downstreamES
downstreamEE
upstream_to_first_count
first_to_downstream_count
first_count
upstream_to_second_count
second_to_downstream_count
second_count
- If the strand is
+
, then the inclusion form includes the 1st exon (1stExonStart_0base
,1stExonEnd
) and skips the 2nd exon - If the strand is
-
, then the inclusion form includes the 2nd exon (2ndExonStart_0base
,2ndExonEnd
) and skips the 1st exon
- If the strand is
- A3SS, A5SS:
longExonStart_0base
longExonEnd
shortES
shortEE
flankingES
flankingEE
across_short_boundary_count
long_to_flanking_count
exclusive_to_long_count
short_to_flanking_count
- The inclusion form includes the long exon (
longExonStart_0base
,longExonEnd
) instead of the short exon (shortES
shortEE
)
- The inclusion form includes the long exon (
- RI:
riExonStart_0base
riExonEnd
upstreamES
upstreamEE
downstreamES
downstreamEE
upstream_to_intron_count
intron_to_downstream_count
intron_count
upstream_to_downstream_count
- The inclusion form includes (retains) the intron (
upstreamEE
,downstreamES
)
- The inclusion form includes (retains) the intron (
- SE:
summary.txt
: Brief summary of all alternative splicing event types. Includes the total event counts and significant event counts. By default, events are counted as significant if FDR <= 0.05. Summary can be regenerated with different criteria by running rMATS_P/summary.py
--tmp
contains the intermediate files generated by the prep step:
[datetime]_[id].rmats
: Summary generated from processing a BAM file[datetime]_bam[sample_num]_[replicate_num]/Aligned.sortedByCoord.out.bam
: Result of mapping input FASTQ files[datetime]_read_outcomes_by_bam.txt
: Counts of the reads used from each BAM file along with counts of the reasons that reads could not be used