Abstract
EL/Sea (EL) mice have a 100% incidence of defect of the third molars (M3) and are used as animal specimens for the study of tooth loss.
Previous studies reported that a reg ion flanked by 61.8 cM and 66.2 cM in chromosome 3 was involved in the defect of M3 of EL, and named this gene absence of the third molars (am3).
In the meantime, it was also found that EL mice are animal specimens for the stu dy of fused roots of the upper first molar and epilepsy.
The purpose of the present study was to find whether there was a difference in the incidence of the defects of M3 between the upper and lower jaw, and whether the appearance of fused roots of the upper first molar and epilepsy are controlled by am3.
Although the number of M3 in EL congeni c mice did not show any differences between right and left in the jaw, the upper M3 rather than the lower one was more strongly visible in EL congenic mice.
This result suggests that am3 strongly affects the loss of upper M3 though am3 affects both the upper and lower by the M3.
EL congenic mice ha d the same frequency of fused roots of the upper first molar and epilepsy as EL mice.
These results suggest that am3 is not related to the appearance of fused roots of the upper first molar and epilepsy.
