Correlation between ASE determined using allele fractions and normalized allele ratios. The ASE levels determined according to the difference in allele fraction [A1/(A1 + A2)] between SNPs in RNA and DNA are shown on the x-axis. The fold overexpression of one allele according to the allele ratios (A1/A2) for SNPs in RNA normalized against the allele ratio for SNPs in DNA are shown on the y-axis. Mean values from triplicate assays of 3531 informative SNPs in 197 ALL samples are shown (∼700,000 data points).