  In a supersymmetric model, the presence of a right handed neutrino with a
large Yukawa coupling $f_{\nu}$ would affect slepton masses via its
contribution to the renormalization group evolution between the grand
unification and weak scales. Assuming a hierarchichal pattern of neutrino
masses, these effects are large for only the third generation of sleptons. We
construct mass combinations to isolate the effect of $f_{\nu}$ from mass
corrections already expected from tau Yukawa couplings. We then analyze the
size of these effects, assuming that the Super-Kamiokande data constrain 0.033
eV $\alt m_{\nu_{\tau}} \alt 0.1$ eV and that neutrino masses arise via a
see-saw mechanism. We also explore whether these effects might be detectable in
experiments at future $e^+e^-$ linear colliders. We find that $m_{\tnu_{\tau}}$
needs to be measured with a precision of about 2-3% to measure the effect of
$f_{\nu}$ if the neutrino and top Yukawa couplings unify at the grand
unification scale. In a simple case study, we find a precision of only 6-10%
might be attainable after several years of operation. If the neutrino Yukawa
coupling is larger, or in more complicated models of neutrino masses, a
determination of $\ttau_1$ and $\tnu_{\tau}$ masses might provide a signal of a
Yukawa interaction of neutrinos.
