Phased mutation count and parental age. The number of phased mutations identified from seven rhesus macaque trios attributed to paternal (red) and maternal (blue) transmission. There is a strong linear relationship between the number of transmitted paternal mutations and the paternal age at conception (R² = 0.78; Poisson regression, P = 7.5 × 10⁻⁴). The number of maternally transmitted mutations was not significantly associated with the maternal age at conception in our data (R² = 0.29; Poisson regression, P = 0.11). Shaded areas show respective regression 95% CI. These seven trios represent cases in which mutations can be tracked through the following generation (Supplemental Fig. S1).