Table 5.

Chromosome-wide SNP and LD summary statistics

Population	Statistic	Chr 6	Chr 21	Chr 22
African-American	No. of SNPs	9129	3418	3688
	SNP spacing on covered segments (kb)^a
	Mean	10.1	7.9	7.3
	Median	6.9	4.5	4
	Minor allele frequency
	Mean	0.29	0.3	0.29
	Median	0.28	0.3	0.29
	Decay of LD (kb)
	\|D′\| half length	28.9	19	18.2
	r² half length	16.4	11.8	9.9
	Swept radius	41	22.1	21.8
Caucasian	No. of SNPs	9274	3551	3931
	SNP spacing on covered segments (kb)^a
	Mean	9.9	7.6	7
	Median	6.7	4.1	3.7
	Minor allele frequency
	Mean	0.31	0.31	0.31
	Median	0.31	0.32	0.32
	Decay of LD (kb)
	\|D′\| half length	46	29.5	29.3
	r² half length	26.7	19.2	19.3
	Swept radius	56.3	31.2	30.9
Chinese	No. of SNPs	10,916	3567	3496
	SNP spacing on covered segments (kb)^a
	Mean	11.7	8.2	7.7
	Median	8.3	5.8	4.7
	Minor allele frequency
	Mean	0.3	0.3	0.3
	Median	0.3	0.3	0.3
	Decay of LD (kb)
	\|D′\| half length	41.7	31.2	31.8
	r² half length	27.5	20.4	21.8
	Swept radius	50.2	31.3	31.6
Japanese	No. of SNPs	10,825	3536	3483
	SNP spacing on covered segments (kb)^a
	Mean	11.8	8.3	7.8
	Median	8.4	5.9	4.6
	Minor allele frequency
	Mean	0.3	0.3	0.31
	Median	0.31	0.31	0.3
	Decay of LD (kb)
	\|D′\| half length	44	32.8	34
	r² half length	28.9	21.1	21.1
	Swept radius	53.1	34.6	33

↵a Covered segments are defined as intervals where inter-SNP distances are ≤50 Kb

The linkage disequilibrium maps of three human chromosomes across four populations reflect their demographic history and a common underlying recombination pattern