Mandible shape analysis in a testicular feminization (Tfm) strain of mice.

The role of androgens on the sexual dimorphism of mandible shape was investigated in mice carrying the X-linked gene for testicular feminization (Tfm), which is known to determine a profound insensitivity to testosterone and is associated with a severe reduction in androgen receptor levels in Tfm/Y males. Mandible shape analysis in an inbred strain of mice segregating for the Ta (tabby) and Tfm mutations showed that the sexual dimorphism observed between +Ta/+Ta females and +Ta/Y males almost disappeared between Tfm+/+Ta females and Tfm+/Y males. In addition, a canonical discriminant analysis showed that these two closely related classes, Tfm+/+Ta and Tfm+/Y, are readily differentiated from both the +Ta/+Ta and +Ta/Y classes. These results suggest that androgens are involved in the mandible shape sexual dimorphism and play a role in mandibular development in both males and females.