GenMAPP analysis requires that the raw data is pre-processed into a form that can be used by GenMAPP. Pre-processing typically includes things like background adjustment, normalization and probe-level summarization, but since each experiment is unique it is not possible to make recommendations as to exactly what type of pre-processing should be done. Because of this, the below instructions list a set of typical pre-processing steps which does not represent a solution for all datasets.
Background adjustment and normalization algorithms are typically included in array image processing applications, so these algorithms may be applied to your data by the core lab or facility that processes the arrays. Similarly, summarizing the data at the level of probes (for Affymetrix arrays) is commonly done at this stage as well, before the data reaches the end user. Since there are many algorithms available that will all have different effects on the data, consulting a statistician in regards to your specific dataset is advised.
To use GenMAPP, the complete dataset (all arrays) must be contained in one file. If the data is not immediately available in this summary format, all relevant files must be combined. Most often this means combining separate data files containing data for individual arrays into one file, but it can also mean combining different types of data.
Combining data into one spreadsheet
Any type of metric or parameter can be used to color genes in GenMAPP, including text-based parameters. Calculating the metrics can be done in several ways, for example programmatically, in a database program or most commonly in Excel.
Before import to GenMAPP, the data needs to be formatted according to GenMAPP specifications. Briefly, this includes adding a System Code column containing a system code for each entry and organizing the columns to have a GenMAPP supported ID in the first column and the System Code as the second column. For details on how to do this, see the Expression Dataset Manager.
Formatting data for import to GenMAPP
Once the data is properly formatted, it can be imported to GenMAPP via the Expression Dataset Manager:
Importing data using the Expression Dataset Manager
To create Color Sets for your dataset, use the Criteria Builder in the Expression Dataset Manager. For detailed instructions, see Expression Dataset Manager.
Creating Color Set in the Expression Dataset Manager