a, Genotype covariance (above diagonal) and sharing of f2 variants (below diagonal) between pairs of individuals. b, Quantification of average f2 sharing between populations. Each row represents the distribution of f2 variants shared between individuals from the population indicated on the left to individuals from each of the sampled populations. c, The average number of f2 variants per haploid genome. d, The inferred age of f2 variants, as estimated from shared haplotype lengths, with black dots indicating the median value.