Tigr MultiExperiment Viewer is a freely available tool for analyzing normalized microarray data. It can be used to perform statistical analysis, clustering, classification and visualization of the data.
MeV can be downloaded at http://www.tm4.org/mev.html
Loading data into MeV
Data in the following formats can be loaded into MeV:
- .mev files- MeV expression files
- .tav files- TIGR Array Viewer format
- TDMS files - Tab delimited file containaing spot annotation in the left hand columns and expression values for each sample as right hand columns. When loading, user needs to specify where the first expression column begins.
- .gpr file - GenePix file
- Affymetrix file format
After data is loaded into MeV, it can be adjusted by using the options under the Adjust Data Adjustments such as mean centering, median centering and log transformations can be done. The data can also be filtered based on quality and variance.
Remember that the expression image may look very different after a data adjustment such as log transformation is done. You may need to change the color scale limits (under Display menu) according to the limits of your adjusted data to see an accurate expression image.
The following statistical tests can be performed on the data using MeV:
- Two-factor Anova
- Multiple testing corrections- Bonferroni, adjusted Bonferroni. Bonferroni correction is a very stringent correction while adjusted Bonferrroni is a more lenient correction.