Unity of elementary particles and forces in higher dimensions

We present a model in which elementary particles and forces are unified in the framework of quantum field theory in higher dimensions. The particles include gauge bosons, quarks and leptons, as well as the Higgs bosons and the forces include strong, weak, hypercharge as well as Yukawa interactions. The model is based on a simple group SO(16) in six dimensions with N=2 supersymmetry. The gauge symmetry, as well as supersymmetry is broken to SU(4) x SU(2)_L x SU(2)_R x U(1)^3 with N=1 supersymmetry upon compactification in four dimension on a T^2/Z_6 orbifold.