We then examined whole-exome sequencing data (∼150× average coverage) from 214 TCGA ovarian carcinoma samples33 to determine whether detection power was related to the number of mutations actually observed. For each sample, we calculated the proportion of loci for which the local coverage provided at least 80% power to detect mutations present at single copy in a subclone present at 5%. Those samples with the lowest proportion of such well-powered loci tended to be 2 those in which the least mutations were detected (r2 = 0.24, P = 2.7×10-13; Supplementary Fig. 7f), suggesting that the failure to find such mutations was due to the lack of power. This result also demonstrates the importance of power calculations for characterization of the subclonal frequency spectrum.
