TABLE 1.

Null distribution of IBD probabilities: proportions of estimated IBD probabilities less than specified values for non-IBD regions

	Probabilities at individual locations			Probabilities maximized over regions
	<0.01	<0.1	<0.5	<0.01	<0.1	<0.5
30 kb	0.938	0.983	0.991	0.25	0.88	0.96
3 kb	0.976	0.994	0.996	0.67	0.94	0.95
Chromosome 1	0.991	0.996	0.997	0.97	0.99	0.99
Chromosome 21	0.998	1.000	1.000	0.95	1.00	1.00

IBD probabilities were estimated for pairs of non-IBD haplotypes. In addition to considering probabilities estimated at individual locations, the maximum estimated IBD probability in each region was noted. The proportions of estimated IBD probabilities taking values <0.01, 0.1, and 0.5 at individual locations (“Probabilities at individual locations”) and maximized over the region (“Probabilities maximized over regions”) are shown. Rows correspond to different marker densities: 30-kb average spacing (100 markers per region), 3-kb average spacing (400 markers), and subsets of 300 consecutive markers taken from chromosomes 1 and 21 of the Affymetrix 500K panel.