  Spin-1 spin-orbit-coupled spinor Bose-Einstein condensates have been realized
in experiment. We study spin-orbit-coupled spinor gap solitons in this
experimentally realizable system with an optical lattice. The spin-dependent
parity symmetry of the spin-orbit coupling plays an important role in
properties of gap solitons. Two families of solitons with opposite
spin-dependent parity are found. Using an approximating model by replacing the
optical lattice with a Harmonic trap, we demonstrate the physical origination
of these two families. For a large negative quadratic Zeeman shift, we also
find a type of gap solitons that spontaneously breaks the spin-dependent parity
symmetry due to the ferromagnetic spinor interactions.
