(A) Percentage of lines with LOH (loss of heterozygosity). Each black dot represents an autosome and the red dot represents X and Y. LOH in male and female lines are separately displayed on the X and Y-axes. (B) Percentage of cell lines with either one (n = 119, 34.80% of male cell lines) or two Xa’s (n = 108, 31.58% of male cell lines), cell lines with partial X’s are not included. (C) Expression level of XIST in male cell lines, [Y] means with or without Y chromosome. (D) Expression ratios of X-linked genes between Xa[Y] and XaXa[Y] cell lines. Each grey dot represents a gene, and significant differences are indicated by black dots (t-test, p<0.05). (E) Expression level of XIST in female cell lines with or without LOH. Female lines with LOH have very low levels of XIST, suggesting all X's being active. In non-LOH (XaXb) lines, the expression of XIST indicates the presence of inactive X’s. (F) Percentage of cell lines with either one (n = 30,10.79% of female cell lines) or two Xa’s (n = 31, 11% of female lines) in female lines with LOH of whole X chromosome. Non-LOH lines are not used because of the uncertainty in the number of Xa’s.