  A new ansatz for quark and lepton mass matrices is proposed in the context of
supersymmetric grand unified theories. The 13 parameters describing fermion
masses and mixings are determined in terms of only 6 free parameters, allowing
7 testable predictions. The values of $V_{us}$, $V_{cb}$, $V_{ub}$, $m_u$,
$m_d$, $m_s$, and $m_b$ are then predicted as a function of the 3 charged
lepton masses, $m_c$, $m_t$, and $\tan \beta$, the ratio of Higgs vacuum
expectation values. In particular the Cabibbo angle and $m_s/m_d$ are
determined in terms of only lepton masses. All predictions are in very good
agreement with experiments.
