The Psyllid Expression Network (PEN) is an interactive tool to visualize high resolution gene expression data. These help pages explain several ways to query the expression data and to visualize the results, enabling the comparison of the expression profiles of several genes simultaneously, as well as to visualize co-expression information. One section describes how to download the expression data in a format that is easy to export to spreadsheet software and to generate figures that are ready for presentations or publications.

A case study is included here to illustrate how to use the PEN to identify genes of interest that are coexpressed with a candidate gene.

1. Three ways to explore gene expression.
   
   
   1. Search gene expression using gene ID.
   2. Search gene expression using BLAST.
   3. Search gene expression for a custom list.


2. Selecting the conditions of the experiment.
   
   
   1. Projects.
   2. Correlation filter.
   3. Selection of the conditions.


3. Expression viewer output options.
   
   
   1. Expression Cube.
   2. Expression bar graphs.
   3. Expression images.
   4. Heatmap.
   5. Downloading the results.


4. How to find putative genes of interest.