We have also created a high-resolution map of recurrent genetic abnormalities in hiPSCs and identified plausible candidate targets of selection. The majority of these recurrent loci are rare and were not reliably identified in previous studies with smaller sample sizes. Compared to previous work11,12, we observed substantially lower levels of genetic aberrations. One possible explanation is that access to donor-matched reference samples helped us more accurately identify germline CNAs that would otherwise have inflated our estimates, while previous studies in ESCs were unable to perform similar comparisons.
