Expected vs observed frequency of nuclei with biallelic expression in females.

Efficiency (p) of RNA-FISH hybridisation was determined from the results obtained in male fibroblasts and extrapolated to determine the expected frequency of nuclei with two signals, one signal and no signal per cell using the formula p2+2pq+q2 = 1, where p2 is the number of nuclei with two signals, 2pq represents nuclei with one signal and q2 is the number with no signal. P-values were determined by a χ2 test with 2 degrees of freedom.