Multiplex PCR genotyping strategy. (A) Schematic representation of primers and transcripts within the Cdan1 gene. (B) PCR products after multiplex PCR amplification. Amplification products from cell-line DNA of Cdan1^gt/wt mESCs (positive control) and Cdan1^wt/wt mESCs (E14, negative control) are compared with mouse tail-derived DNA to demonstrate stability of assay to identify murine live gene-trapped animals. (C) Codanin-1 mRNA expression of wild-type (E14, Cdan1^wt/wt) and gene-trapped (XG571, Cdan1^gt/wt) mESCs by quantitative PCR normalized to expression from housekeeping gene GAPDH.