Position of the deletion in the Ap3d1 gene in mocha mice. A) Outline of the Ap3d1 gene with exons (red) and introns (blue). The deletion in the mocha mice is illustrated by the orange box in the wild type Ap3d1 gene. The position of the genotyping primers are shown on both the WT and mocha genes. B) Sequencing of the mocha Ap3d1 gene reveals the deletion site, which shares a CATCT motif in both the upstream and downstream sequence. Alignment of the mocha Ap3d1 gene with the WT gene shows that the mutated Ap3d1 gene contains the first 1–6770 bp and the last 17409–18539 bp. The dashed box illustrates the position of the repeated CATCT sequence. Nucleotides only present in the WT sequence, and deleted in mocha mice, are colored orange.