  We demonstrate that sea quark effects of a magnitude expected from
renormalization group considerations are clearly visible in the strong coupling
constant measured in current full QCD simulations. Building on this result an
estimate of $\alpha_{\overline{MS}}^{(5)}(M_Z)$ is made employing the
charmonium $1S-1P$ mass splitting calculated on full QCD configurations
generated with two flavors of dynamical Kogut-Susskind quarks to fix the scale.
