  Formation of quark and lepton mass matrices through intermediate states of
heavy mirror fermions is capable of reproducing main qualitative properties of
weak mixing matrices (CKM and PMNS matrices). The reproduction includes the
hierarchy of CKM matrix elements, a general form of the PMNS matrix, involving
the smallness of the neutrino mixing angle \theta_{13}, and leads to very small
neutrino masses. For leptons, these properties appear only for the Dirac nature
of SM neutrino and its inverse spectrum. In such a lepton system, not only do
spontaneous mirror symmetry violation and the observed mass hierarchy of
charged leptons (e,\mu,\tau) govern the structure of the PMNS matrix but also
permit assessment of its allowed complexity, that is, the CP properties of
leptons. The PMNS matrix then contains no Majorana phases and its Dirac phase
\delta_{CP} corresponds to |\sin\delta_{CP}|, which is significantly smaller
than unity.
