We identified outlier samples by comparing AF values to either a constant (BRCA2, PTCH1, TP53, CSMD3) or to the range of values possible from mixing of the subclones (ERBB4, MET, SAAL1–LRP1B AF was used as the predictive variable) (Fig. 6A; see Methods). The gene discussed is ERBB4; the disease is atrial fibrillation.