Chapters:
Chapters function normally with a single exception. They grant a Characteristic Aptitude based on their bonus characteristic. A Space Marine may choose either characteristic that was boosted by their Chapter and gain an Aptitude in that characteristic. If possible, they must choose an aptitude they do not already have. If that is not possible, they may gain any other Characteristic Aptitude as normal for duplicate Aptitudes.
Chapters function normally with a single exception. They grant a Characteristic Aptitude based on their bonus characteristic. A Space Marine may choose either characteristic that was boosted by their Chapter and gain an Aptitude in that characteristic. If possible, they must choose an aptitude they do not already have. If that is not possible, they may gain any other Characteristic Aptitude as normal for duplicate Aptitudes.