How can I confirm that two coding sequence (CDS) features are in the same reading frame?
Ensure that Both Features are Translated CDS
To display each feature translation in Sequence view, double-click the feature or select the feature and choose Features → Edit Feature... . Then click the Translate this feature in Sequence view check box.

View the Translation Junction in Sequence View
In Sequence view, scroll to the junction of the feature translations. If the two features are in frame, they will be vertically aligned.
If the two features are in frame, the extended translation from the upstream feature will be on the same line as the translation of the downstream feature, and the two features will be connected by a dotted arrow.
Note: The upstream feature should not include a stop codon to ensure that translation extends beyond the end of the feature.

Out-of-Frame Example
If the two features are not in frame, the extended translation from the upstream feature will not be on the same line as the translation of the downstream feature.
