  We develop a systematic analysis of quark mass matrices which, starting with
the measured values of quark masses and mixing angles, allows for a model
independent search for all possible (symmetric or hermitian) mass matrices
having texture zeroes at the unification scale. A survey of all six and five
texture zero structures yields a total of five possible solutions which may be
distinguished by improved measurements of the CKM matrix elements and which may
readily be extended to include lepton masses with the Georgi-Jarlskog texture.
The solutions naturally suggest a parameterisation for the mass matrices based
on a perturbative expansion and we present some speculations concerning the
origin of such structure.
