  Employing the perturbative treatment of gravitational clustering, we discuss
possible effects of primordial non-Gaussianity on the matter power spectrum. As
gravitational clustering develops, the coupling between different Fourier modes
of density perturbations becomes important and the primordial non-Gaussianity
which intrinsically possesses a non-trivial mode-correlation can affect the
late-time evolution of the power spectrum. We quantitatively estimate the
non-Gaussian effect on power spectrum from the perturbation theory. The
potential impact on the cosmological parameter estimation using the power
spectrum are investigated based on the Fisher-matrix formalism. In addition, on
the basis of the local biasing prescription, non-Gaussian effects on the galaxy
power spectrum are considered, showing that the scale-dependent biasing arises
from a local-type primordial non-Gaussianity. On the other hand, an
equilateral-type non-Gaussianity does not induce such scale-dependence because
of weaker mode-correlations between small and large Fourier modes.
