a- e: Haplotype block partitioning for simulated chromosome 18. Ten haplotype blocks were selected from the simulation of chromosome 18 for algorithm assessment. Blocks are identified by an integer ID shown across the top of the figure, indicating relative position within the 1000 SNPs simulated. The true bounds for each block are shown as gray vertical lines, with the thickness of the line indicating the block size. Each horizontal line represents a haplotype block called by the four gamete rule(a), Gabriel et al. method(b), or LD-Spline using a D' threshold of 1(c), 0.8(d), or 0.6(e), with the length of the line representing the number of SNPs included in the haplotype block call. The x-axis illustrates the upper and lower SNP index in the dataset for each block, and the y-axis indicates the dataset for which each block is called.