Figure 1

Correspondence of expression detection between microarrays and MPSS. Chi-square statistics was used as a measure of data correspondence in terms of absent/present call made by each microarray platform versus each MPSS library. For microarray data, a fixed definition of the "Present/Absent" call based on quality flags and filtering status for each gene. For MPSS data, a gene (UniGene clusters) was considered "Present" if the copy number was above a given threshold, otherwise it was considered "Absent". The "Present/Absent" call threshold varied from 1 to 100 tpm for MPSS in steps of 1 and Chi-square statistics were calculated for each threshold. Part (a) shows how the p-values from these comparisons varied with threshold on data for MRP1, and part (b) shows the same for MRP2.