||P.130 left column bottom paragraph: "[Investigators] sequenced the genomes of three multi-sibling families, identified candidate DNMs [de novo mutations] and validated 768 of them by targeted resequencing. Both the average genome-wide mutation rate of 1.28 × 10^−8 mutations per nucleotide per generation and the ratio of paternal to maternal mutations (3.5) are slightly higher than but compatible with previous estimates [ref 6]. On average, the number of mutations in the child increased approximately linearly by 2.9 mutations with each additional year in the parents' ages. The magnitude of this effect differed by a factor of greater than two between families." P.131 left column top paragraph: "Whereas all DNMs showed a 3.5:1 ratio of paternal to maternal mutations, these early mutations were compatible with a 1:1 ratio of paternal and maternal origin, as might be expected given the occurrence of these mutations before sexual differentiation of the embryo."