Supergravitational Production of "Flavor and Color"
  A conventional graviton vertex operator is generated from the gauging of global supersymmetry. If the outgoing gravitino is replaced by a fermion-boson pair of like helicity, and if a new principle of equivalence associates supergravity with the introduction of color, then every quark flavor can be described as a gravitationally excited lepton. In this context, A SUSY SU(5)can be constructed exclusively of leptons and their scaler superpartners (or of quarks and their superpartners). This SUSY GUT flavor symmetry, which is preserved by the proposed supergravity interactions, accounts for three fermionic generations and predicts a new quark--aleft-handed (non-strange) version of the strange quark. 
Joseph Towe