Genomic DNA from tips of mouse tails obtained at ~10 d of age was genotyped in a single PCR reaction with the following primers: Apc-Int13F2 (GAGAAACCCTGTCTCGAAAAAA) and Apc-Int13R2 (AGTGCTGTTTCTATGAGTCAAC), resulting in 320-bp and 430-bp products from the wild-type and conditional ApcCKO allele, respectively.