How can I specify a nonstandard genetic code for a translated feature?
Select the Feature
The following procedure can be performed when you first create a translated feature, but the lesson will assume that the translated feature already exists.
In this example, the Actin CDS feature from the ciliate Tetrahymena thermophila, contains stop codons due to translation using the standard genetic code.
To change the genetic code click the CDS feature to select it.

Hover over the CDS feature to see a tooltip. If no genetic code is noted, then the Standard genetic code is being used for translation.
Edit the Feature
To open the Edit Feature dialog, click Features → Edit Feature.... Alternatively, double-click the feature.
To open the Feature Translation Options dialog, click Feature Translation Options... .

Open the Feature Translation Options Dialog
Choose the Genetic Code
Use the Genetic Code dropdown menu to choose the desired genetic code.

The dialog will show the new translation and allow you to confirm the translation. Click OK.

View the Updated Feature Translation

Close both dialogs by clicking OK. The updated genetic code will now be used in the translation. In this example genetic code the TAA and TAG codons are translated to Q (Glutamine) rather than the standard stop codon.
Hover over the CDS feature to see a tooltip. The new genetic code is noted.