Doubly Lopsided Mass Matrices from Supersymmetric SU(N) Unification
  It is shown that in supersymmetric SU(N) models with N>5 the so-called doubly lopsided mass matrix structure can emerge in a natural way. The non-trivial flavor structure is entirely accounted for by the SU(N) gauge symmetry and supersymmetry, without any flavor symmetry. The hierarchy among the families results directly from a hierarchy of scales in the chain of breaking from SU(N)to the Standard Model group. A simple SU(7) example is presented. 
S. M. Barr