Single Channel Options
Transcript data from single channel platforms (e.g. Affymetrix) can be displayed in three ways:

• Log2 transcript count - Maps reported transcript counts by taking the log base 2 of the count and mapping 0 to black and saturating values to the positive expression color (red or yellow)
• Per-gene log2 fold change - Calculates fold changes on a per-gene basis by dividing reported transcript counts by the average count for the gene, then performs a log base 2 transformation. Positive values are mapped to red or yellow, negative values are mapped to green or blue
• Rank based - Displays the expression level ranks in gray scale, showing the condition with the lowest expression level as black and the condition with the highest expression level as white.