Figure 4. Departures from simple crossover interference.

(a) Inferred escape parameter as a function of maternal age. Mothers were divided into 10 approximately equal-sized deciles on the basis of age, and the Housworth–Stahl interference escape model was fitted for each group separately. The inset shows the estimates of the escape parameter when considering phase-known (blue, n=2184) and phase-unknown (green, n=6968) individuals separately. Estimates for ν show no correlation with age (Supplementary Fig. 9). Error bars indicate 95% confidence intervals. (b) Distribution of inter-crossover distances for young and old mothers, where the boundary between young and old is taken as median maternal age (30 years). Error bars represent a 95% confidence interval assessed via 1000 bootstrap samples, and the arrow highlights a significant difference between the young and old groups for tightly clustered events. The inset shows the cumulative distribution function (CDF) up to 5 cM. (c) Distribution of inter-crossover distances for young and old fathers, where the boundary between young and old is taken as median paternal age (32 years).