PCR validation of candidate splicing events. PCR products are derived from forward/reverse primers in well-annotated flanking regions as indicated under the gene name. The interpretation of each change in mobility is given to the right ("Incl", include; "Ext", extended). The sample numbers match those in the sample data information (see Methods). Note that in several cases, an unlabeled doublet band results from a heteroduplex forming between the PCR products. Controls are "Universal Total RNA" (Clontech), an independent colon RNA sample (BioChain) and a No Template Control ("NTC"). "M" is a DNA ladder marker.