How can I specify a nonstandard genetic code for translations?
Open the Translation Options Dialog

To open the Translation Options dialog, click View → Translation Options... .

Alternatively, click the side toolbar "Choose translated sequences" menu button, then click Translation Options... .
Choose the Translation Genetic Code

Expand the Genetic code for ORFs and new features menu, then choose the desired genetic code.

To apply the selected genetic code to existing features, click the check box. Close the dialog by clicking OK.
View the Updated Translation

The updated genetic code will now be used in the translations.
Note: The nonstandard genetic code name is highlighted in yellow.
Review the Genetic Code Table

To review the selected genetic code translation table, click Tools → Genetic Code Tables. Mouse over the window matrix to highlight redundant translations.