A Model for Fermion Mass Hierarchies and Mixings

We present a model which contains three Abelian symmetries beyond the standard model. One is anomalous {\it \` a la} Green-Schwarz, and family-independent; the other two are family symmetries. All are broken at a large scale by stringy effects. The model is predictive in the neutrino sector: large mixing between $\nu_\mu-\nu_\tau$, and {\cal O}$(\lambda^3)$ $\nu_e-\nu_\mu$ mixings. Its natural cut-off is the gauge unification scale, orders of magnitude below the perturbative string cut-off.