Given Talk at Moriond 2006: Fermion Mass in E6 GUT with Discrete Family   Permutation Symmetry S3
  A discrete symmetry S3 easily explains all neutrino data. However it is not obvious the embedding of S3 in GUT where all fermions live in the same representation. We show that embedding S3 in E6 it is possible to make distinction between neutrinos and the rest of matter fermions. 
Stefano Morisi