a: Inferred IBD among pairs of 10,156 ancient Eurasian individuals. The plot visualizes both the count (y-axis) as well as the summed length (x-axis) of all IBD at least 12 cM long. b: Simulated IBD among pairs of relatives. For each relative class, we simulated 100 replicates using the software PEDSIM [Caballero et al., 2019], as described in Supp. Note S6. As in a we depict the summed length and the count of all IBD at least 12 cM long. c: Inferred IBD among four ancient English Neolithic individuals, who lived about 5,700 years ago and were entombed at Hazleton North long cairn. A full pedigree was previously reconstructed using first and second-degree relatives inferred using pairwise SNP matching rates [Fowler et al., 2022]. We depict all IBD at least 12 cM long. The four individuals were genotyped using 1240k aDNA capture (I12438: 3.7x average coverage on target, I12440: 2.1x, I13896:1.1x, I12439: 6.7x)