Table 2.

Levels of REP1 expression from Xi chromosomes

Cell line	Xi/Xa	Inactive X
51	0.42  ±  0.06	Normal X
67	0.22  ±  0.02	Normal X
53	0.16  ±  0.03	Normal X
152	0.11  ±  0.02	i(X)(p22)
140	0.06  ±  0.01	dic(X;22)
146	0.05  ±  0.01	Normal X
48	≤0.01	Normal X
52	≤0.01	der(X)
128	≤0.01	Normal X

Levels of Xi expression are indicated relative to Xa expression, as determined in nonrandomly inactivated fibroblast cell lines (see Materials and Methods). Each cell line was assayed at least twice, and averages ± one SD are indicated.