STITCHING THE YUKAWA QUILT

We develop a systematic analysis of quark mass matrices which, startin g with the measured values of quark masses and mixing angles, allows f or a model-independent search for all possible (symmetric or hermitian ) mass matrices having texture zeroes at the unification scale. A surv ey 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 inclu de lepton masses with the Georgi-Jarlskog texture. The solutions natur ally suggest a parameterisation for the mass matrices based on a pertu rbative expansion and we present some speculations concerning the orig in of such structure.