This tool can be used to create scatter plot of p-value versus fold change for microarray data. The graph is composed of six regions. The plot style for each region can be individually customized.
Download the file VolcanoPlot.opx, and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps Gallery window.
- Click the Volcano Plot icon in the Apps Gallery window to open the dialog.
- Choose XY data from a worksheet: fold change for X and p-value for Y. If gene names or probe set IDs are available in the worksheet, choose them as Label.
- If X data is linear, check Log2 Transform for X check box to convert to log 2 scale.
- In Cutoff Values group, specify cutoff values for P-value and Fold Change. P-value must be between 0 and 1. Fold change must be larger than 1. Both of these two cutoff values are linear scale.
- Check Show Reference Lines option to add a horizontal line for the cutoff P-value and two vertical lines for the cutoff fold change in the plot.
- To customize symbol color or size for each region of the plot, double click on the region to open Plot Details dialog, and change settings in the Symbol tab.
- To customize reference line style, right click on the line, then choose Properties from the context menu. In the Object Properties dialog, change settings in the Line tab.