Figure 1. Submental-vertex cephalographs of C57BL/6J (A) and DBA/2J mice (B). The zygomatic arch width was measured between points Zb and Zc (horizontal arrow), and the snout length was measured between points I and Za (vertical arrow). (C) Distribution of the zygomatic arch width measurements (Zb-Zc) of F2 mice. Each blue square represents a measurement from an F2 mouse. The average Zb-Zc measurements of C57BL/6J (red line) and DBA/2J (yellow line) are 2.60 (SD ± 0.18) mm and 3.16 (SD ± 0.10) mm, respectively. The differences between the average measurements of C57BL/6J and DBA/2J mice are statistically significant (p = 0.0102). (D) One hundred and ten F2 mice were subjected to the cephalometric analysis and the whole-genome microsatellite QTL analysis.