  Parton distributions in the small $x$ region are numerically predicted by
using a modified DGLAP equation with the GRV-like input distributions. We find
that gluon recombination at twist-4 level obviously suppresses the rapid growth
of parton densities with $x$ decrease. We show that before the saturation scale
$Q^2_s$ is reached, saturation and partial saturation appear in the small $x$
behavior of parton distributions in nucleus and free proton, respectively. The
antishadowing contributions to the saturation phenomena are also discussed.
