Similar to Kong et al. (2008) [12], we took each individual in turn and at each locus we calculated the number of other individuals that share an IBD segment (excluding closely related individuals with relatedness ). We then took the average across all loci on chromosome 10 for each individual and plotted the distribution of this average IBD sharing in Figure 2 (right). The average IBD sharing is a function of both the sample size and the amount of relatedness between individuals in the population. Split again clearly has very small amounts of IBD sharing whilst the other cohorts have broadly similar distributions. It is notable that all cohorts have some individuals with surrogate parent on average while some individuals have surrogate parents.
