Genotyping of mocha mice. Agarose gel electrophoresis of a genotyping-PCR. Using the primers described in table 1, mocha mice resulted in an 847 bp PCR product and wild types generated a 677 bp product while both bands were clearly evident in heterozygotes, as expected. Lane 1: GeneRuler 100 bp Plus DNA ladder (Fermentas, Vilnius, Lithuania), lane 2: mocha homozygote (847 bp) (Ap3d1 -/-), lane 3: heterozygote (Ap3d1 +/-), lane 4: AP-3 wild type (677 bp) (Ap3d1 +/+). The genotyping protocol worked well in both newborn and adult mice.