What is Qualimap?¶
Qualimap is a platform-independent application written in Java and R that provides both a Graphical User Interface (GUI) and a command-line interface to facilitate the quality control of alignment sequencing data. Shortly, Qualimap:
- Examines sequencing alignment data according to the features of the mapped reads and their genomic properties
- Povides an overall view of the data that helps to to the detect biases in the sequencing and/or mapping of the data and eases decision-making for further analysis.
The main features offered by Qualimap are:
- fast analysis across the reference genome of mapping coverage and nucleotide distribution;
- easy-to-interpret summary of the main properties of the alignment data;
- analysis of the reads mapped inside/outside of the regions defined in an annotation reference;
- computation and analysis of read counts obtained from intersting of read alignments with genomic features;
- analysis of the adequacy of the sequencing depth in RNA-seq experiments;
- support for multi-sample comparison for alignment data and counts data;
- clustering of epigenomic profiles.
Download the ZIP file from the Qualimap web page.
Unpack it to desired directory.
Run Qualimap from this directory using the prebuilt script:
Qualimap was tested on GNU Linux and MacOS.
On MS Windows use script qualimap.bat to launch Qualimap.
The JAVA runtime can be downloaded from the official web-site. There are prebuilt binaries available for many platforms.
R enviroment can be downloaded from R project web-site.
In general the installation of R environment is platform-specific and may require additional efforts.
Several Qualimap features are implemented in R, using a number of external packages.
If R environment is not available or required R-packages are missing, “Counts QC” and “Clustering” features will be disabled.
Currently Qualimap requires the following R-packages:
- optparse (available from CRAN)
- NOISeq, Repitools, Rsamtools, GenomicFeatures, rtracklayer (available from Bioconductor)
One can install these packages manually or by executing the script found in the installation folder:
Installing Qualimap on Ubuntu¶
This manual is specific for Ubuntu(Debian) Linux distribution, however with slight differences this can be applied for other GNU Linux systems.
It is possible to use openjdk:
sudo apt-get install openjdk-6-jre
The R latest version can be installed from public repos.
The repos must be added to the sources file. Open sources.list:
sudo gedit /etc/apt/sources.list
Add the following line:
deb http://<my.favorite.cran.mirror>/bin/linux/ubuntu <name.of.your.distribution>/
List of cran mirrors can be found here
Here is an example for Ubuntu 10.04 (Lucid):
deb http://cran.stat.ucla.edu/bin/linux/ubuntu lucid/
Then install R:
sudo apt-get update
sudo apt-get install r-base-core
If you don’t have the public key for the mirror add it:
gpg --keyserver subkeys.pgp.net --recv-key <required.key>
gpg -a --export <required.key> | sudo apt-key add -
More details available here:
Qualimap needs R version 3.1 or above. This can be checked with the following command:
Alternatively it is possible to build R enviroment directly from sources downloaded from r-project.org.
Install required R-packages¶
Some packages depend on external libraries, so you might need to install them either:
sudo apt-get install libxml2-dev
sudo apt-get install libcurl4-openssl-dev
You can install required packages manually or use special script from Qualimap installation folder:
sudo Rscript $QUALIMAP_HOME/scripts/installDependencies.r
where $QUALIMAP_HOME is the full path to the Qualimap installation folder.
If you use Qualimap 2 for your research, please cite the following:
Okonechnikov, K., Conesa, A., & García-Alcalde, F. (2015). “Qualimap 2: advanced multi-sample quality control for high-throughput sequencing data.” Bioinformatics, btv566
The first version of the tool was described in the following manuscript:
García-Alcalde, et al. “Qualimap: evaluating next generation sequencing alignment data.” Bioinformatics(2012) 28 (20): 2678-2679