  The observed hierarchy of the quark and lepton masses and mixing angles has
led to the parametrisation of the mass matrices in powers of the Cabibbo angle
and a certain number of zeros. The origin of these ``textures'' may lie in
symmetries present at the GUT/string unification scale. We discuss the case of
an extra $U(1)$. Symmetric textures with two or three zeros can be generated
through high-order operators containing light/heavy Higgs multiplets and
singlet fields. However, a realistic scenario for generating both the up- and
down-quark mass matrices is not possible within the MSSM with an extra singlet.
The presence of at least one pair of heavy Higgs multiplets and extra singlets
are needed, and, even so, difficulties are encountered when extending this
scenario to the neutrino sector through the mass relations of grand
unification.
