Dual Channel Options
Expression data from dual channel platforms (e.g. Agilent) can be displayed in three ways:

• Reported log2 fold change - Uses reported fold change values by mapping under-expression to the negative color (green or blue) and over-expression to the positive color (red or yellow).
• Centered per-gene fold change - Same as above, but subtracts the average fold change from expression values on a per gene basis
• 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.