How do I see and use MW markers if they are not displayed in the default list?
SnapGene has hundreds of commercial and common ladders or molecular weight markers (MW markers) that you can use with your agarose gel simulations. Not all markers are listed by default. Follow the instructions below to add or remove markers in the default list.
Customize the Default List of MW Markers
If a preferred MW marker is not listed in the MW Marker dropdown menu, click Edit MW Markers List....
Alternatively, click SnapGene → Preferences (macOS) or Edit → Preferences (Windows or Linux), and select "Agarose Gels" in the sidebar, then click Edit MW Markers List....

Click the disclosure triangles to expand each Supplier section and see all ladders for that section.
Click the check box next to a desired ladder to add it to the default list.
To remove a ladder from the default list, locate the ladder and click to uncheck.
Click OK to keep the changes.

The added ladders will now be available to use in the "MW Marker" dropdown.