In the CEU and YRI trios respectively, 3,236 and 2,750 candidate de novo germline single base mutations were selected for further study, based on their presence in the child but not the parents. Of these, 1,001 (CEU) and 669 (YRI) were validated by resequencing the cell line DNA. When these were tested for segregation to offspring (CEU) or in non-clonal DNA from whole blood (YRI), only 49 CEU and 36 YRI candidates were confirmed as true germline mutations. Correcting for the fraction of the genome accessible to this analysis provided an estimate of the per generation base pair mutation rate of 1.2×10−8 and 1.0×10−8 in the CEU and YRI trios respectively. These values are similar to estimates obtained from indirect evolutionary comparisons32, direct studies based on pathogenic mutations33, and a recent analysis of a single family34.
