  Symplectic flavour symmetry group Sp(n/2) (n is even) of n Majorana states
does not allow for invariant Majorana masses. Only specific mass matrices with
diagonal and nondiagonal elements are possible here. As a result of the
spontaneous violation of flavour and chiral symmetries, a mass matrix could
appear only for the number of flavours n = 6 and only together with
R,L-symmetry violation (i.e., parity violation). The see-saw mechanism produces
here three light and three heavy Dirac particles (neutrinos). The peculiarity
of the observed light neutrino spectrum: two states located far from the third
one, can be explained by certain simple properties of mass matrices appearing
in Sp(3). The ordering of the states corresponds to normal mass hierarchy.
Situation, when neutrino mass differences are significantly less than masses
themselves, appears to be unrealizable here. Mixing angles for neutrinos can
not be determined without understanding formation mechanisms for charged lepton
spectrum and Majorana state weak currents.
