  We show that the chiral $SU(n)\otimes SU(n)$ flavor symmetry on the
null-plane severely restricts the sea quarks in the baryon octet. It predicts
large asymmetry for the light sea quarks $(u,d,s)$, and universality and
abundance for the heavy sea quarks. Further it is shown that existence of the
heavy sea quarks constrained by the same symmetry reduces the theoretical value
of the Ellis-Jaffe sum rule substantially.
