Screenshot of the ExpressionView applet

ExpressionView is an R package that provides an interactive environment to explore biclusters identified in gene expression data. A sophisticated ordering algorithm is used to present the biclusters in a visually appealing layout. From this overview, the user can select individual biclusters and access all the biologically relevant data associated with it. The package is aimed to facilitate the collaboration between bioinformaticians and life scientists who are not familiar with the R language.


Requirements and installation

Download the R package (includes the Flash applet)

To use the ExpressionView R package you will need a working GNU R installation.

As of the 23rd of April, 2010, the ExpressionView package is an official BioConductor package.

ExpressionView depends on a number of other R packages: isa2, Biobase, AnnotationDbi, etc. The good news is that all these dependencies are installed automatically, and all you need to do is to start R and type in


at your R prompt. See the ExpressionView package page at the BioConductor website for details.

Alternatively, you can also download the package from here:

The Flash applet requires a Flash-enabled web browser. Please install Adobe Flash Player from the Adobe web site if your browser does not have it yet.

Download the stand-alone viewer (Adobe AIR)

If you prefer a stand-alone viewer, you can download and install the Adobe AIR build ExpressionView.air (right-click to download file).
To run the program, you need the AIR runtime environment which you can get from Adobe.
ExpressionView creates files associations to .evf files, allowing you to simply double-click on such files to launch the viewer and load the data.

Download sample data


The ExpressionView package is licensed under the GNU General Public License, version 2 or later. For details, see



There are several tutorials describing how to use ExpressionView. The features of the R package are documented within the program. Just have a look at the ExpressionView help page after you have installed the package. Below, you can download the tutorial presenting the basic workflow and the description of the ordering algorithm. For the Flash applet, we have produced a few videos showing you how to use the program.

Getting started with ExpressionView

HTML PDF Rnw R code

Ordering algorithm used in ExpressionView


ExpressionView File Format


ExpressionView R package manual


Flash applet

Installing the stand-alone version

Additional documentation and downloads

The ExpressionView data file is an XML file. We have created a corresponding XML Schema file that defines its structure.

The Flash applet is written in ActionScript. It is open source and can be built from the command line using the Adobe Flex SDK or more conveniently with the Adobe Flex Builder IDE. For more information, visit the Flex website.

For the Flash applet, we have implemented components that could also be used in other applications. The most important one being the LargeBitmapData class that allows one to work with BitmapData of arbitrary size. In the standard BitmapData class, the maximum size for a BitmapData object is 8,192 pixels in width or height, and the total number of pixels cannot exceed 16,777,216 pixels. Note that the ResizablePanel class is no longer used in ExpressionView.