  All quark mass matrices with texture zeroes obtained through weak basis
transformations are confronted with the experimental data. The reconstruction
of the quark mass matrices M_u and M_d at the electroweak scale is performed in
a weak basis where the matrices are Hermitian and have a maximum of three
vanishing elements. The same procedure is also accomplished for the Yukawa
coupling matrices at the grand unification scale in the context of the Standard
Model and its minimal supersymmetric extension as well as of the two Higgs
doublet model. The analysis of all viable power structures on the quark Yukawa
coupling matrices that could naturally appear from a Froggatt-Nielsen mechanism
is also presented.
