Yukawa sector in nonsupersymmetric renormalizable SO(10)

We discuss the ordinary, nonsupersymmetric SO(10) as a theory of fermion masses and mixings. We construct two minimal versions of the Yukawa sector based on (126) over bar (H) and either 10(H) or 120(H). The latter case is of particular interest since it connects the absolute neutrino mass scale with the size of the atmospheric mixing angle theta(A). It also relates the smallness of V-cb with the largeness of theta(A). These results are based on the analytic study of the second and third generations. Furthermore, we discuss the structure of the light Higgs and the role of the Peccei-Quinn symmetry for dark matter and the predictivity of the theory.