Graphical output of Primer-Check for SEC23IP (P125) showing the discrepancy between variants targeted by the Affymetrix U133A array probe sets and Taqman (ABI) primer and probe setsused by Dallas and co-workers. Four distinct splice variants of SEC23IP are displayed. Orange vertical lines indicate the target positions of the microarray probes. Probe set 209175_at targets two of four variants, and probe set 216392_at targets three of four variants. The light blue vertical lines show the context sequence location for the qRT-PCR ABI Taqman primer/probe set that targets all splice variants. The dissimilarity of splice variant coverage between qRT-PCR primers and microarray probes creates the potential for discordant expression values, depending on which mix of variants is expressed in the sample being studied.