Genetic characteristics of double hypoglossal canal as a nonmetric trait

The hypothesis that the hypoglossal canal bridging or double (HGCD), a nonmetric cranial trait, is a powerful discriminator between populations (Dodo, 1980, 1987) is still controversial. To examine this issue, the incidences of HGCD were investigated in six inbred mice strains (CBA, C57BL, BALB/c, Strong A, NZB, and DAB) and one group of wild mice, six matings of CBA and C57BL, and four experimental diet groups. The above hypothesis was supported by some results such as no effects of diet on the incidences of HGCD and significant differences among the incidences of HGCD in some inbred strains. However, significant differences were also detected in the incidences of HGCD among groups within an inbred strain. Therefore, we think that further conservative and experimental assessments should be performed to determine the usefulness of incidences of HGCD as a powerful discriminator in skeletal studies on populations and family history.