A computer-implemented method for determining minor variants. The method includes receiving electropherogram sequence data from a test sample, identifying any non-primary peaks in the electropherogram, and characterizing identified non-primary peaks using at least one signal feature. The method may further include analyzing the at least one signal feature across identified non-primary peaks to identify variant candidates, evaluating at least one peak characteristic of each of the identified variant candidates, and classifying variant candidates as bona fide variants based on the evaluation of peak characteristics.