Supplementary Fig. 1 Mean observed copy number of autosomal SNPs (black circles, solid line) and X chromosomal SNPs (blue diamonds, solid line) for each DNA sample is plotted against X chromosome number. Mean copy numbers of X-chromosomal SNPs were as follows (± standard deviation): XO, 1.18 ± 0.44; XX, 2.15 ± 0.55; 3X, 3.00 ± 0.99; 4X, 3.73 ± 0.74; 5X versus XX, 4.48 ± 1.01.